HUTCHISON'S 
PHYSIOLOGY 
?l   AND  HYGIENE 


,  MAYNARD,MERRILL,6  CO. 


LIBRARY 

OF  THE 

UNIVERSITY  OF  CALIFORNIA 


OF" 


BIOLOGY 

U1RARY  Class 

G 


NEW  EDITION.    1902 


A   TREATISE 


ON 


PHYSIOLOGY    AND    HYGIENE 

FOR  EDUCATIONAL  INSTITUTIONS 
AND   GENERAL  READERS 


BY 

JOSEPH  C.  HUTCHISON,  M.D.,  LL.D. 

EX-PRESIDENT  OF  THE  NEW  YORK   PATHOLOGICAL  SOCIETY,  EX  VICE-PRESIDENT  Of 

THE  NEW  YORK  ACADEMY  OF  MEDICINE,   SURGEON   TO   THE  BROOKLYN 

CITY  HOSPITAL,   LATE   PRESIDENT  OF  THE   MEDICAL  SOCIETY 

OF  THE   STAa-B  OF  NEW  YORK,   ETC.,  ETC. 


UNIVERSITY  LIBRARY, 
ULIFORW.A. 


NEW  YORK 

MAYNARD,   MERRILL,  &  CO. 
1904. 


V* 


8IOLOGT 
LIBRARY 

G 


COPYRIGHT,  1895,  1902, 

BV 

MAYNARD,  MERRILL,  &  Co. 


TO  MY  WIFE 

WHOSE  SYMPATHY  HAS,  FOR  MORE  THAN  TWENTY  YEAR% 
LIGHTENED  THE  CARES  INCIDENT  TO 

AN  ACTIVE  PROFESSIONAL  LIFE 
THIS  HUMBLE  VOLUME 

IS   AFFECTIONATELY   INSCRIBED. 


144854 


PUBLISHERS'  NOTE  TO   REVISED  EDITION 

THE  sales  of  this  work  have  in  the  last  few  years  become  so  large  that 
it  has  been  found  necessary  to  make  new  electrotype  plates.  The  pub- 
lishers have  taken  advantage  of  this  to  have  the  book  carefully  examined 
with  a  view  to  discovering  whether  or  no  it  conformed  in  every  respect 
to  the  latest  advances  in  knowledge  of  the  subject.  Very  few  changes 
in  the  text  have  been  found  necessary,  and  these  few  are  of  such  a  minor 
character  as  not  in  any  way  to  prevent  the  use  of  the  new  and  old 
editions  in  the  same  class. 

The  main  changes  to  be  noted  in  this  edition  are  as  follows  :  Topical 
Outlines  have  been  added  at  the  end  of  chapters,  which  it  is  believed  will 
be  of  great  value  to  pupils  and  teachers.  In  some  of  them  additional 
information  has  been  given,  which  it  has  not  been  thought  best  to  include 
in  the  text,  but  which  may  be  found  useful  for  the  teacher  in  his  class 
work. 

Such  slight  changes  have  been  made  in  the  text  as  were  necessary  to 
meet  the  requirements  of  the  laws  of  the  several  states  with  respect  to 
the  influence  of  alcohol  and  narcotics.  The  book  Will  be  found  to  comply 
fully  with  all  such  laws  and  with  the  intelligent  temperance  sentiment  of 
the  country. 

A  chapter  on  emergencies  has  also  been  added,  which,  it  is  hoped,  will 
give  the  book  a  permanent  value  in  the  home  and  be  of  service  to  the 
many  " first  aid  to  the  injured"  classes  that  are  being  formed  in  all  parts 
of  the  country. 

A  number  of  new  illustrations  have  been  scattered  through  the  book. 
The  only  other  change  of  any  prominence  is  in  the  experiments,  which  in 
the  former  edition  have  been  in  the  appendix,  but  are  now  transferred  to 
the  body  of  the  book  as  footnotes,  where  they  will  be  more  accessible  as 
an  aid  to  the  teacher  in  more  interestingly  presenting  the  subject  to  the 
class.  All  the  experiments,  as  well  as  the  anatomical  demonstrations, 
are  simple,  and  the  teacher  will  have  no  difficulty  in  reproducing  them. 
Should  there  be  failure  at  first,  a  little  patience  and  a  few  trials  will  soon 
be  followed  by  success.  All  complex  dissections  on  recently  killed 
animals,  as  well  as  all  vivisections  upon  frogs,  etc.,  have  purposely  been 
omitted,  not  only  because  they  are  unnecessary  in  teaching  the  rudiments 
of  anatomy  and  physiology,  but  also  because  they  would  create  disgust 
and  abhorrence  in  the  majority  of  pupils. 

The  publishers  gratefully  acknowledge  their  indebtedness  to  D.  L. 
Bard  well,  Superintendent  of  Public  Instruction,  Binghamton,  New  York, 
who  has  made  such  changes  in  the  text  as  were  necessary  to  bring  it  into 
perfect  accord  with  the  latest  Syllabus  of  the  Board  of  Regents  of  the 
State  of  New  York. 

NEW  YORK,  May  15,  1902. 


PREFACE 


THIS  work  is  designed  to  present  the  leading  facts  and 
principles  of  human  physiology  and  hygiene  in  clear  and 
concise  language,  so  that  pupils  in  schools  and  colleges,  and 
readers  not  familiar  with  the  subjects,  may  readily  compre- 
hend them.  Anatomy,  or  a  description  of  the  structure  of 
an  organ,  is  of  course  necessary  to  the  understanding  of  its 
physiology,  or  its  uses.  Enough  of  the  former  study  has, 
therefore,  been  introduced  to  enable  the  pupil  to  enter  intel- 
ligently upon  the  latter. 

Familiar  language^  as  far  as  practicable,  has  been  em- 
ployed, rather  than  that  of  a  technical  character.  With  a 
view,  however,  to  supply  what  might  seem  to  some  a  defi- 
ciency in  this  regard,  a  Pronouncing  Glossary  has  been  added, 
which  will  enable  the  inquirer  to  understand  the  meaning 
of  many  scientific  terms  not  in  common  use. 

In  the  preparation  of  the  work  the  writer  has  carefully 
examined  all  the  best  material  at  his  command,  and  freely 
used  it;  the  special  object  being  to  have  it  abreast  of  the 
present  knowledge  on  the  subjects  treated,  as  far  as  that  is 
possible  in  a  work  so  elementary  as  this.  The  discussion  of 
disputed  points  has  been  avoided,  it  being  manifestly  inap- 
propriate in  a  work  of  this  kind. 

The  aim  of  a  text-book  on  physiology  for  schools  and  col- 
leges should  be  to  present  in  the  simplest  and  clearest  pos- 
sible manner  the  well-established  facts  of  the  subject  to  be 
taught,  so  that  the  students  may  obtain  an  intelligent  idea  of 
the  workings  and  uses  of  the  human  body.  It  should  be 


6  PREFACE 

scientific  enough  to  be  clear  and  logical,  and  to  appeal  to 
reason,  not  a  mere  compilation  of  facts  to  be,  learned  by  rote. 
To  make  it  preparatory  to  a  higher  course  in  physiology 
would  be  manifestly  a  mistake,  for  it  would  necessitate  a 
much  more  scientific  plan  of  arrangement,  and  the  introduc- 
tion of  an  amount  of  material  which  would  be  confusing. 
The  teaching  of  anatomy  and  physiology  in  schools  should  be 
considered  chiefly  as  an  aid  in  teaching  hygiene,  so  that  the 
student  may  learn  how  to  live  a  healthful  life. 

The  writer  desires  to  acknowledge  his  indebtedness  to  VR.  M. 
Wyckoff,  M.D.,  for  valuable  aid  in  the  preparation  of  the 
manuscript  for  the  press;  and  to  E.  Cresson  Stiles,  M.D.,  a 
skillful  microscopist  and  physician,  for  the  chapter  "  On  the 
Use  of  the  Microscope  in  the  Study  of  Physiology ." 


CONTENTS 


INTRODUCTORY  CHAPTER 

CELL   STRUCTURE 

Divisions— Cells  — Structure  of  the  Cell  — Cell  Reproduction— Cell 
Nourishment  —  Cell  Motion 

CHAPTER  I 

THE   FRAMEWORK    OF   THE   BODY 

PAGB 

The  Bones  — Their  Form  and  Composition —  The  Properties  of  Bone 

—  The    Skeleton — The    Joints — The    Spinal     Column — The 
Growth  of  Bone  — The  Repair  of  Bone—  Changes  in  the  Skele- 
ton—Erect  Position 17 

CHAPTER  H 

THE    MUSCLES 

The  Muscles  —  Flexion  and  Extension — The  Tendons — Contrac- 
tion—  Physical  Strength  —  Necessity  for  Exercise  —  Its  Effects — 
Forms  of  Exercise  —  Walking  —  Hiding  —  Gymnastics  —  Open- 
air  Exercise —  Excessive  Exercise  —  Sleep  —  Recreation.  ...  33 

CHAPTER  HI 

THE    INTEGUMENT,    OR    SKIN 

The  Integument  —  Its  Structure —  The  Nails  and  Hair —  The  Com- 
plexion—  The  Sebaceous  Glands — The  Perspiratory  Glands  — 
Perspiration  and  its  Uses  —  Importance  of  Bathing  —  Different 
Kinds  of  Baths  —  Manner  of  Bathing  —  The  Benefit  of  the  Sun 

—  Importance  of  Warm  Clothing  —  Poisonous  Cosmetics     ...      56 

CHAPTER  IV 

THE    CHEMISTRY   OF   FOOD 

The  Source  of  Food  —  Inorganic  Substances— Water — Salt — 
Lime  —  Iron — Organic  Substances  —  Albumen,  Fibrin,  and 
Caseine—  The  Fats  or  Oils—  The  Sugars,  Starch,  and  Gum- 
Stimulating  Substances —  Necessity  of  a  Regulated  Diet  ...  75 

1 


8  CONTENTS 

CHAPTER  V 

FOOD   AND   DRINK 

PAGE 

Necessity  for  Food —  Waste  and  Repair  —  Hunger  and  Thirst  — 
Amount  of  Food  —  Renovation  of  the  Body  —  Mixed  Diet  —  Milk 

—  Eggs  —  Meat  —  Cooking  —  Vegetable  Food  —  Bread  —  The 
Potato  —  Fruits  —  Purity  of  Water — Action  of  Water  upon  Lead 

—  Coffee,  Tea,  and  Chocolate  —  Effects  of  Alcohol 91 

CHAPTER  VI 

DIGESTION 

The  Principal  Processes  of  Nutrition  — The  General  Plan  of  Di- 
gestion —  Mastication —  The  Teeth — Preservation  of  the  Teeth 

—  Insalivation  —  The  Stomach  and  the  Gastric  Juice  —  The  Move- 
ments of  the  Stomach  —  Gastric  Digestion —  The  Intestines — The 
Bile  and  Pancreatic  Juice  —  Intestinal  Digestion  —  Absorption  by 
Means  of  Blood-vessels  and  Lacteals  —  The  Lymphatic  or  Absorb- 
ent System  —  The  Lymph  —  Conditions  which  affect  Digestion  — 
The  Quality,  Quantity,  and  Temperature  of  the  Food —  The  Influ- 
ence of  Exercise  and  Sleep  —  The  Kidneys  —  The  Spleen  —  Effect 

of  Alcohol  upon  Digestion,  the  Liver,  and  Kidneys 117 

CHAPTER  VII 

THE   CIRCULATION 

The  Blood  —  Its  Plasma  and  Corpuscles  —  Coagulation  of  the  Blood 

—  The   Uses  of  the  Blood — Transfusion — Change  of  Color  — 
The  Organs  of  the  Circulation —  The  Heart,  Arteries,  and  Veins 

—  The  Cavities  and  Valves  of  the  Heart — Its   Vital  Energy  — 

—  Passage  of  the  Blood  through  the  Heart  —  The  Frequency  and 
Activity  of  its  Movements — The  Pulse — The  Sphygmograph  — 
The  Capillary  Blood-vessels  —  The  Rate  of  the  Circulation  —  As- 
similation —  Injuries  .  to  the  Blood-vessels  —  Effects  of  Alcohol 
upon  the  Heart — As  a  Fat- Producer 151 

CHAPTER  VIII 

RESPIRATION 

The  Objects  of  Eespiration — The  Lungs — The  Air  Passages  — 
The  Movements  of  Respiration  —  Expiration  and  Inspiration  — 
The  Frequency  of  Respiration  —  Capacity  of  the  Lungs  —  The 


CONTENTS  9 

PAG» 

Air  we  Breathe  —  Changes  in  the  Air  from  Respiration  —  Changes 
in  the  Blood— Interchange  of  Gases  in  the  Lungs—  Comparison 
between  Arterial  and  Venous  Blood  —  Respiratory  Labor  —  Im- 
purities of  the  Air  — Dust  — Carbonic  Acid  — Effects  of  Impure 
Air  — Nature's  Provision  for  Purifying  the  Air—  Ventilation— 
Animal  Heat 187 

CHAPTER  IX 

THE  NERVOUS  SYSTEM 

Animal  and  Vegetative  Functions — Sensation,  Motion,  and  Volition 

—  The  Structure  of  the  Nervous  System  —  The  White  and  Gray 
Substances — The  Brain  —  Its    Convolutions — The   Cerebellum 

—  The  Spinal  Cord  and  its  System  of  Nerves  —  The  Anterior 
and  Posterior  Roots —  The  Sympathetic  System  of  Nerves —  The 
Properties  of  Nervous  Tissue  —  Excitability  of  Nervous  Tissues  — 
The  Functions  of  the  Spinal  Nerves  and  Cord  —  The  Direction 
of  the  Fibres  of  the  Cord — Reflex  Activity  and  its   Uses —  2 he 
Functions  of  the  Medulla  Oblongata  and  the  Cranial  Ganglia— r 
The  Reflex  Action  of  the  Brain  —  Effects  of  Alcohol,  Tobacco, 
Snuff,  Narcotics,  Opium,  Chloral,  Hasheesh,  Chloroform   .    .    •    217 

'CHAPTER  X 

THE   SPECIAL   SENSES 

The  Production  of  Sensations  —  Variety  of  Sensations  —  General 
Sensibility  —  Pain  and  its  Function  —  Special  Sensation,  Touch, 
Taste,  Smell,  Sight,  and  Hearing  —  The  Hand,  the  Organ  of 
Touch  —  The  Sense  of  Touch  —  Delicacy  of  Touch — Sensation 
of  Temperature  and  Weight —  The  Tongue,  the  Organ  of  Taste 

—  The  Nerves  of  Taste  —  The  Sense  of  Taste,  and  its  Relations 
with  the  other  Senses  —  The  Influence  of  Education  on  the  Taste 

—  The  Nasal  Cavities,  or  the  Organs  of  Smell  —  The  Olfactory 
Nerve—  The  Uses  of  the  Sense  of  Smell  —  The  Sense  of  Sight  — 
Light  —  The  Optic  Nerve  —  The  Eyeball  and  its  Coverings—  The 
Function  of  the  Iris  —  The  Sclerotic,  Choroid,  and  Retina  —  The 
Tears  and  their  Function — The  Movements  of  the  Eyeball  — 
The  Function  of  Accommodation  —  The  Sense  of  Hearing  and 
Sound — The  Ear,  or  the  Organ  of  Hearing — The  External, 
Middle,  and  Internal  Ear 264 


10  CONTENTS 

CHAPTER  XI 

THE    VOICE 

PAGE 

Voice  and  Speech—  Tlie  Larynx,  or  the  Organ  of  the  Voice—  The 
Vocal  Cords  —  The  Laryngoscope  —  The  Production  of  the  Voice 

—  The  Use  of  the  Tongue —  The  Different  Varieties  of  Voice  — 
The  Change  of  Voice  —  Its  Compass  —  Purity  of  Tone — Ven- 
triloquy  321 

CHAPTER  XII 

THE    USE   OP   THE   MICROSCOPE    IN   THE    STUDY   OP   PHYSIOLOGY 

The  Law  of  Tissues  —  Necessity  of  the  Microscope  — Different  Kinds 
of  Microscopes — Additional  Apparatus  —  Preliminary  Studies  — 
The  Study  of  Human  Tissues  —  Tissues  of  the  Inferior  Animals 

—  Incentives  to  Study 333 

CHAPTER  XIII 

FIRST   HELP   IN   ACCIDENTS 

Shock  —  Fainting —  Vertigo  —  Hemorrhage  —  Fractures  and  Dislo- 
cations—  Sprains  —  Burns  and  Scalds  —  Danger  from  'Illumi- 
nating Gas  and  Kerosene  —  Frost-Bites  —  Sunstroke  —  Fits  or 
Convulsions  —  Drowning  —  Poisons  and  their  Antidotes  .  .  .  342 

CHAPTER  XIV 

BACTERIA    AND   DISEASE 

Bacteria  —  Cause  Disease  —  Require  Warmth  and  Moisture  —  Varie- 
ties of  Bacteria  —  Toxines  and  Ptomaines — Antitoxins — De- 
struction of  Bacteria 35S 

APPENDIX 

CARE  OP  THE  SICK-ROOM .  359 

DISINFECTION 361 

HOME  AND  HEALTH 368 

ON  GOING  INTO  THE  COUNTRY 365 

EXERCISES  FOR  HOME  GYMNASTICS 367 

GLOSSARY 370 

.»,,,,,.,,,,,., 381 


LIST  OF  ILLUSTRATIONS 


FRONTISPIECE 

VISCERA  IN  POSITION  PAGE 

1.  Section  of  bone 19 

2.  The  skeleton 20 

3.  Structure  of  bone,  magnified 21 

4.  Section  of  bone,  parallel  to  surface 21 

5.  Ribs  in  natural  and  healthy  state         .....  23 

6.  Ribs  showing  effects  of  tight  lacing 23 

7.  The  ligaments  of  the  wrist 24 

8.  Cells  of  cartilage 24 

9.  Elbow-joint 25 

10.  Spinal  column       .........  26 

11.  The  muscles. 32 

12.  Muscular  tissue,  magnified  .......  34 

Colored   Plate — Striped  muscle  of  crab,  relaxed  and  extended, 

and  human  cardiac  muscle        ....        Opposite  35 

13.  Biceps  muscle  of  the  arm 35 

14.  Muscles  and  tendons  of  the  hand 37 

15.  Lower  portion  of  the  leg 37 

16.  View  of  knee-joint 38 

Colored  Plate — Muscle  and  bladder  of  salamander.       Opposite  42 

17.  The  chest  weight  .                  .                  48 

18.  Root  and  transverse  section  of  hair,  magnified      ...  58 

19.  Magnified  hair  and  section  of  skin 60 

Colored  Plate — Magnified  section  human  skin       .       Opposite  61 

20.  Magnified  view^of  sweat-gland  and  duct       ....  61 

21.  Granules  of  potato  starch 86 

22.  Section  of  the  trunk 119 

23.  Section  of  a  tooth                  120 

24.  Section  of  the  jaws 121 

25.  Section  of  the  jaws — right  side      ......  122 

26.  Structure  of  a  salivary  gland 124 

27.  Head  of  a  horse,  showing  salivary  gland,  etc.       .         .         .  125 

28.  Section  of  chest  and  abdomen 129 

29.  Alimentary  canal 130 

30.  Thelacteals 138 

31.  Intestinal  villi,  magnified 141 

32.  The  kidneys  and  bladder       .         .         .         .         .         .         .144 

Colored  Plate — Circulation  of  the  blood        .        .      Opposite  151 

33.  Blood  corpuscles,  highly  magnified 152 

34.  Blood  corpuscles  of  man  and  lower  animals,  magnified          .  153 

11 


12  LIST  OF  ILLUSTRATIONS 

FIG.  PAGE 

35.  Circulation  of  the  blood,      v 

36.  External  view  of  the  heart,  J     PP°S 

37.  Section  of  the  heart 162 

38.  Valves  of  heart  with  walls  relaxed 163 

39.  Valves  of  heart  during  contraction  of  ventricles          .        .        .  163 

40.  Left  section  of  the  heart,    ) 

41.  Right  section  of  the  heart,  }0pposlte 166 

42.  Form  of  the  pulse 169 

43.  Vein  with  valves  open .        .171 

44.  Vein  with  valves  closed .171 

45.  Web  of  frog's  foot,  magnified 173 

46.  Margin  of  frog's  web   .        .         .         .         .        .        .         .        .  173 

47-.  Organs  of  the  chest 188 

48.  Larynx,  trachea,  and  bronchial  tubes .         .         .         .         .        .  189 

49.  Diagram  and  section  of  the  air-cells 189 

50.  Section  of  the  lungs 190 

51.  Section  of  mouth  and  throat       .......  191 

52.  Ciliated  cells 192 

53.  Ventilation  by  window        .        .        .        ...        .        .        .  209 

54.  Cerebro-spinal  system 220 

55.  Upper  surface  of  the  cerebrum 222 

56.  Vertical  section  of  the  brain 223 

57.  Lower  surface  of  the  brain 224 

58.  Brain  and  spinal  cord  .        .         .         .         .        .         .        .        .  228 

59.  Section  of  spinal  cord  .........  229 

60.  Illustrating  the  functions  of  the  spinal  nerves    ....  234 

61.  An  experiment  with  sense  of  touch 273 

*  62.  Section  of  nasal  cavity        .       - 282 

63.  Front  view  of  the  eye 289 

64.  Vertical  section  of  the  eye,  magnified ......  292 

65.  Front  section  of  eyeball       ........  294 

66.  Diagram  of  blind  point  of  the  eye      .        .        .        .        .        .  296 

67.  The  retinal  image 299 

68.  The  different  shapes  of  the  globe  of  the  eye                .        .        .  301 

69.  The  function  of  accommodation *  .  303 

70.  The  ear  and  its  different  parts     .  307 

71.  Showing  the  internal  mechanism  of  the  ear,  magnified      .        .  309 

72.  Section  of  the  right  ear 311 

73.  Section  of  the  larynx  and  trachea       .         .        .        ...        .324 

74.  A  view  of  the  vocal  cords  by  means  of  the  laryngoscope    .        .  325 

75.  The  different  positions  of  the  vocal  cords  f.        .        .         :        .  326 

76.  Double  convex  and  plano-convex  lenses 334 

77.  Simple  microscope 335 

78.  Compound  microscope 336 


PHYSIOLOGY  AND  HYGIENE 


INTRODUCTORY   CHAPTER 

CELL  STRUCTURE 

Divisions  —  Cells  —  Structure  of  the    Cell  — Cell  Reproduction  —  Cell 
Nourishment  —  Cell  Motion 

1.   Divisions.  —  The  study  of  the  human  body  includes : 

1.  Anatomy,  which  is  the  study  of  the  structure  of  the 
human   body.      This   is    again    subdivided    into,   first,   gross 
anatomy,  which  is  the  study  of  the  structure  of  the  body  as 
made  by  careful  dissection ;  and,  second,  microscopic  anatomy, 
also  called  histology,  which  is  the  minute  study  of  the  various 
tissues  and  organs  composing  the  body,  by  the  aid  of  the 
microscope. 

2.  Physiology,  which  is  the  study  of  the  functions  of  the 
various  organs  and  tissues  of  the  body. 

3.  Hygiene,  which  is  the  study  of  the  best  means  of  pre- 
serving the  body's  health. 

2.  Cells.  —  If  we  examine  a  portion  of  any  one  of  the  struc- 
tures of  the  human  body  under  the  microscope,  we  find  that  it 
is  composed  of  countless  small  bodies,  which  are  called  cells. 
These  cells  have  distinctive  shape,  size,  and  form,  in  each  of 
the  different  structures.  Each  one  of  the  cells  aids  in  the 
function  which  characterizes  its  tissue ;  thus,  for  instance,  the 
many  muscle  cells  composing  one  of  the  muscles  of  the  arm 
contract,  and  their  united  contraction  causes  the  entire  muscle 
to  contract.  And,  again,  of  the  many  cells  composing  the  liver, 
each  aids  in  secreting  its  small  portion  of  bile,  and  in  perform- 
ing its  other  functions. 

1.  What  is  anatomy  ?    Physiology?    Hygiene?    2.  What  are  cells  ? 
13 


14  CELL  STRUCTURE 

3.  Although  the  different  cells  composing  the  many  tissues 
of  the  body  are  all  distinct  in  their  respective  characteristics, 
they  are  yet  all  dependent  upon  each  other  for  the  proper  per- 
formance of  their  work,  just  as  the  individual  persons  compos- 
ing the  population  of  a  large  city  lead  independent  lives,  yet 
are  all  dependent  upon  each  other  for  their  respective  exist- 
ences.    Each  cell  has  a  life  of  its  own ;  it  eats,  digests,  moves, 
and  reproduces  its  own  kinjd,  and  yet  it  is  dependent  for  its 
health  and  life  upon  the  healthy  performance  of  the  functions 
of  all  the  other  cells  of  the  body. 

4.  Structure  of  the  Cell.  —  As  the  type  of  the  simplest  cell 
structure,  we  have  the  best  illustration  in  a  microscopical  ani- 
mal, found  in  stagnant  water,  and  called  the  Amoeba.     It  is 
composed  of  transparent,  jelly-like  material,  enclosed  in  a  very 
thin  membrane,  and  having  a  more  or  less  irregular  shape. 
In  its  interior  we  see  that  a  small  portion  of  its  jelly-like 
material  is  more  opaque  than  the  rest,  as  if  composed  of  a 
number  of  granules.     If  we  observe  this  Amoeba  under  the 
microscope,  we  shall  notice  that  it  has  life,  as  manifested  by 
its  power  to  contract  in  places,  and  in  other  places  to  project  a 
part  of  its  body.     It  feeds  by  enclosing  within  its  substance 
any  particles  which  it  may  take  for  food.     It  retains  them  in 
its  interior  until  it  has  absorbed  therefrom  what  it  can  use, 
when  it  again  partly  opens  itself  at  some  point  near  the  par- 
ticle, and  rejects  or  moves  away  from  what  it  does  not  want. 
It  propagates  itself  by  a  simple  process  of  subdivision ;  that 
is,  it  divides  itself  into  two  unequal  portions,  each  portion 
retaining  some  of  the   granular  matter,  which  seems  to  be 
essential  to  its  existence. 

5.  All  the  cells  of  the  human  body  have  the  following 
essential  "structure :  First,  a  thin  membrane  enclosing  the  cell, 
called  the  cell  wall.     Second,  a  jelly-like  or  granular  material, 
composing  its  body,  called  protoplasm,  and  embedded  in  this 
body  a  more  or  less  round  or  oval  body  of  firmer  consistency 
than  the  cell  mass,  called  the  nucleus,  which,  in  many  cases, 

8.  Describe  cell  life.    4.  The  structure  of  the  cell.    5.  In  what  does  the  essential  struc- 
ture of  the  cell  consist  ? 


CELL  STRUCTURE 


15 


contains  a  still  smaller  body,  or  minute  point,  called  the 
nudeolus. 

6.  The  yolk  of  a  common  hen's  egg  probably  illustrates  this 
best.  If  we  break  the  egg  into  a  saucer,  being  careful  not  to 
break  the  yolk,  we  shall  find  upon  examination  that  the  yolk 
is  held  together  by  a  thin  and  delicate  membrane,  the  cell 
wall.  The  liquid  portion  of  the  yolk  is  the  protoplasm.  And 
we  can  also  ^readily  see,  upon  careful  inspection,  a  compara- 
tively small  speck,  more  opaque,  or  rather  whitish  in  ap- 
pearance, which  is  the  nucleus.  The  nucleolus  cannot  be 
observed  by  the  naked  eye.  The  following  diagram  of  the 
yolk  will  illustrate  these  facts : 


d,  Nucleolus. 
c,  Nucleus. 

b,  Protoplasm, 
a,  CellWalL 


7.  Cell  Reproduction.  —  The  following  series  of  diagrams 
shows  how  simple  the  process  of  cell  reproduction  is.  In  a 
we  have  a  simple  cell ;  in  &  it  has  changed  its  shape  by  elon- 
gating and  constricting  in  its  centre;  in  c  the  same  process 
has  been  continued;  and  in  d  we  have  two  new  cells,  but  no 
parent.  The  identity  of  the  parent  has  been  lost  in  its  off- 
spring. 


8.  Cell  Nourishment.  —  The.  cell  wall  absorbs  nourishment, 
which  soon  becomes  a  part  of  the  general  protoplasm.  Waste 
products  in  a  similar  manner  are  expelled  through  the  cell 
wall.  Some  cells  have  the  power  of  excreting  from  their  food 

6.  Describe  the  four  parts  of  a  cell.  7.  Describe  the  process  of  cell  reproduction. 
A.  How  is  nourishment  obtained  ?  Waste  products  expelled  ? 


16  CELL  STRUCTURE 

a  hard  substance,  called  liine,  and  depositing  the  same  as  a 
kind  of  shell  around  themselves. 

9.  Cell  Motion.  —  It  is  reasonable  to  suppose  that  many  of 
the.  cells  of  the  human  body  are  capable  of  some  motion, 
although  this  cannot  be  demonstrated,  except  in  very  few  in- 
stances. It  is  easy  to  demonstrate  that  the  white  corpuscles 
of  the  blood  are  capable  of  independent  motipn,  very  similar 
to  that  of  the  Amoeba.  They  are  able  to  push  their  way 
through  the  walls  of  the  capillaries,  and  thus  wander  through 
all  parts  of  the  body. 

9.  What  range  of  motion  has  a  oett? 


CHAPTER  I 

THE  FRAMEWORK  OF  THE  BODY 

The  Bones  —  Their  Form  and  Composition  —  The  Properties  of  Bone 
—  Histology —  The  Skeleton— The  Joints — The  Spinal  Column- 
Cartilage  —  The  Growth  of  Bone  —  The  Repair  of  Bone  —  Changes 
in  the  Skeleton  —  Erect  Posture 

1.  The  Bones.  —  The  framework  which,  sustains  the  human 
body  is  composed  of  the  bones.     The  superstructure  consists 
of  the  various  organs  on  which  the  processes  of  life  depend. 
These  organs  are  soft  and  delicately  forme* I,  and,  if  unprotected, 
would,  in  most  cases,  rapidly  be  destroyed  when  subjected  to 
violence,  however  slight.      The  bones,  having  great  strength 
and  power  of  resistance,  afford  the  protection  required. 

2.  The  more  delicate  the  organ,  the  more  completely  does 
Nature  shield  it.     For  example:  the  brain,  which  is  soft  in 
structure,  is  enclosed  on  all  sides  by  a  spherical  box  of  bone ; 
the  eye,  though  it  must  be  near  the  surface  of  the  body,  to 
command  an  extensive  view,  is  sheltered  from  injury  within 
a  deep  recess  of  bone ;  the  lungs,  requiring  freedom  of  motion 
as  well  as  protection,  are  surrounded  by  a  large  "chest"  of 
bone  and  muscle.   The  bones  serve  other  useful  purposes.   They 
give  permanence  of  form  to  the  body,  by  holding  the  softer 
parts  in  their  proper  places.     They  assist  in  movement,  by 
affording  points  of  attachment  to  those  organs  which  have 
power  of  motion  —  the  muscles.      For  all  movements  of  the 
body  as  a  whole,  and  for  nearly  all  movements  of  parts  of  the 
body,  save  those  controlling  the  vital  processes,  the  bones  are 
levers. 

3.  The  Form  and  Composition  of  the  Bones.  —  The  shape  and 
size  of  the  bones  vary  greatly  in  different  parts  of  the  body, 
but  generally  they  are  arranged  in  pairs,  one  for  each  side  of 

1.  The  framework  of  the  body?    The  superstructure  ?    2.  Use  of  bones? 

17 


18  THE  FRAMEWORK  OF  THE  HODY 

the  body.  Some  bones  are  long  and  cylindrical,  like  the 
humerus;  some  are  short  and  thick,  lik^  the  bones  of  the 
wrist;  some  are  flat  and  thin,  like  the  bones  of  the  skull; 
some  are  irregular  in  shape,  like  the  vertebrae.  The  longest 
bone  of  the  human  body  is  the  femur,  wh^ch  may  be  as  much 
as  eighteen  inches  in  length ;  from  this  the  size  of  different 
bones  varies  greatly  all  the  way  to  the  tiny  bones  in  the  middle 
ear.  Bones  are  composed  of  both  mineral  and  animal  matter, 
united  in  the  proportion  of  two  parts  of  the  former  to  one  of 
the  latter.  The  mineral  matter  is  chiefly  phosphate  of  lime; 
the  animal  matter  is  gelatin.  We  may  separate  each  of  these 
substances  from  the  other  for  examination.  First,  if  we  burn 
a  bone  for  several  hours  on  a  good  bed  of  coals,  the  gelatin  is 
entirely  removed.  There  remains  a  beautiful  white  specimen 
of  phosphate  of  liine,  which  preserves  the  shape  of  the  bone 
perfectly,  but  is  brittle  and  incapable  of  sustaining  any  con- 
siderable weight.  To  remove  the  mineral  matter  we  use  acid. 
A  sheep's  rib,  thoroughly  cleaned,  or  bones  from  a  roast  fowl, 
should  be  allowed  to  stand  in  dilute  muriatic  acid  (one  part 
acid  to  eight  parts  water)  for  two  or  three  days,  when  the 
phosphate  of  lime  will  be  dissolved  and  only  the  gelatin 
remain,  but  as  before,  the  shape  of  tre  bone  is  preserved, 
the  bone  being  now,  however,  soft  and  pliable.  The  specimen 
may  be  preserved  in  alcohol. 

4.  If,  for  any  reason,  either  of  these  ingredients  is  dispro- 
portionate in  the  bone  during  life,  the  body  is  in  danger.  The 
mineral  substance  is  useful  in  giving  rigidity  of  form,  while 
the  animal  substance  insures  toughness  and  elasticity,  so  that 

1.  Some  Properties  of  Bone.  — "  The  power  of  bone  to  resist  decay  is 
remarkable.  Fossil  bones  deposited  in  the  ground  long  before  the  appear- 
ance of  man  upon  the  earth  have  been  found  by  Cuvier,  exhibiting  a 
considerable  portion  of  cartilage.  The  jaw  of  the  Cambridge  Mastodon 
contained  over  forty  per  cent  of  animal  matter  —  enough  to  make  a  good 
glue  —  and  others  about  the  same.  From  this  we  see  that  a  nutritious 
soup  might  be  made  from  the  bones  of  animals  that  lived  before  the 
creation  of  man.  The  teeth  resemble  bone  in  their  structure,  but  resist 
decay  longer ;  they  are  brought  up  by  deep-sea  dredging,  when  all  other 
parts  of  the  animal  have  wasted  away.  The  bones  differ  at  different  ages, 


3.   Shape  of  bones  ?    Size  ?    Composition  ?    4.  Animal  and  mineral  substance  ? 


THE  FRAME WORK  OF  THE  BODY  19 

by  their  union  we  are  able  to  withstand  greater  shocks  than 
would  be  possible  with  either  alone.  In  youth,  the  animal 
portion  is  in  excess;  a  bone  then  does  not  break  so  readily, 
but,  when  broken,  unites  with  great  rapidity  and  strength. 
On  the  other  hand,  the  bones  of  old  persons  are  more  easily 
broken,  and  in  some  cases  fail  to  unite.  The  mineral  matter 
being  then  in  excess  indicates  that  the  period  of  active  exer- 
tion is  drawing  to  a  close.  (Read  Note  1.) 

5    The  Structure  of  the  Bones.  —  If  we  examine  one  of  the 
long  bones,  which  have  been  sawed  through  lengthwise,  we 


FIG.  1.  — SECTION  OF  BONE.  — A,  Longitudinal. 
B,  Transverse 


observe  that  it  is  admirabFy  fashioned  for  affording  lightness 
as  well  as  strength  (Fig.  1).  Its  exterior  is  hard  and  resisting, 
but  it  is  porous  at  the  broad  extremities,  while  through  the 
central  portion  there  is  a  cavity  or  canal  which  contains  an 
oily  substance  called  marrow.  The  broad  extremities  furnish 
abundant  surface  for  the  formation  of  joints  and  for  the 
attachment  of  muscles;  they  are  porous  so  that  weight  may 

and  under  different  social  conditions.  In  the  disease  called  'rickets,' 
quite  common  among  the  ill-fed  children  of  the  poor  in  Europe,  but  some- 
what rare  in  America,  there  is  an  inadequate  deposit  of  the  mineral 
substance,  rendering  the  bones  so  flexible  that. they  may  be  bent  almost 
like  wax.  In  females  and  weak  men  the  bones  are  light  and  thin,  while 
in  a  powerful  frame  they  are  dense  and  heavy.  Exercise  is  as  necessary 
to  the  strength  of  bone  as  to  the  strength  of  muscle  ;  if  a  limb  be  disused, 
from  paralysis  or  long  sickness,  the  bones  lose  in  weight  and  strength  as 
well  as  the  soft  parts.  Bone  is  said  to  be  twice  as  strong  as  oak,  and,  to 
crush  a  cubic  inch  of  it,  a  pressure  equal  to  5000  pounds  is  requisite." 


5.  The  structure  of  the  bones  ? 


20 


THE  FRAMEWORK  OF  THE  BOD7 


FIG.  2.  —  THE  SKELETON 


THE  FRAMEWORK  OF   THE  BODY 


21 


not  be  increased  with  enlarged  size.  The  cylindrical  portion 
of  a  long  bone  is  called  the  shaft,  which  is  hollow  for  the 
accommodation  of  the  marrow,  and  also  for  the  purpose  of 
obtaining  a  maximum  strength  with  a  minimum  weight. 
This  principle  is  well  illustrated  in  iron  construction  work, 
where  supporting  columns  are  made  hollow. 

6.   Histology  of  Bone.  —  If  a  thin  section  of  bone  be  exam- 
ined under  the  microscope,  we  discover  that  it  is  pierced  by 

.1 


FIG.  3.  —  STRUCTURE  OF  BONE 
ENLARGED 

numerous  fine  tubes,  about 
which  layers  of  bone-sub- 
stance are  arranged.  Fig- 
ure 3  gives  a  good  idea  of 
this  microscopic  structure 
of  a  human  long  bone. 
The  Haversian  canals  (a), 
named  in  honor  of  their 
discoverer,  carry  blood ; 
the  tiny  radiating  lines 
represent  the  canaliculi  (c) 
(little  canals),  which  carry  blood  and  lymph  to  the  lacunce  (b) 


FIG.  4.  —  SECTION  PARALLEL  TO  THE  SURFACE  FROM 
THE  SHAFT  OF  THE  FEMI  it.  —  MAGNIFIED  100 
DIAMETERS.  — a,  Haversian  canals  ;  6,  c,  Lacuna; 


2.  Experiment.  —  Obtain  one  of  the  long  bones  of  the  sheep  or  calf, 
scrape  it  thoroughly  clean,  but  do  not  detach  the  cartilage  covering  the 
ends.  Saw  it  through  crosswise  in  the  middle ;  then  saw  the  upper  half 
through  lengthwise.  (See  Fig.  1.) 


6.  What  are  the  Haversian  canals  ?    Canaliculi  ?    Lacuna;  ? 


22  THE  FRAMEWORK  OF  THE  BODY 

(lakes).  In  each  lacuna  is  a  living  cell,  called  a  bone-corpuscle. 
These  bone-corpuscles  feed  on  nourishment  brought  to  them 
through  the  canaliculi ;  and  deposit  about  themselves  layers  of 
gelatin  and  phosphate  of  lime.  These  layers  are  called  lamel- 
lae, and  make  the  matrix  of  the  bone.  These  lamellae  are  well 
shown  in  Fig.  3. 

7.  Another  element  of  power  is  found  in  the  curved  out- 
line of  the  bones.      The  curved  line  is  said  to  be  "the  line 
of  beauty/7  as  it  certainly  is  the  line  of  strength.     It  is  uni- 
formly present  in  the  bones  whose  position  exposes  them  to 
accident.     The  surface  of  all  bones,  except  the  articulating 
surfaces  at  the  ends,  is  covered  by  a  tough  membrane,  called 
periosteum.     This  is  pierced  by  numerous  openings  through 
which  pass  the  blood-vessels  which  carry  the  blood  to  and  into 
the  bones. 

8.  The  Skeleton.  —  The  bones  in  the  human  body  number 
two  hundred  and  six,  and  when  joined  together  in  their  proper 
places,   form   what    is    termed    the    skeleton   (Fig.   2).      The 
skeleton   embraces   three   important   cavities.      The    first   of 
these,  surmounting  the  frame,  is  a  box  of  bones,  called  the 
skull;  below  this  is  a  bony  case,  or  "chest"  ;  and  again  below 
this,  separated  only  by  a  thin  muscular  membrane,  called  the 
diaphragm,  is  the  abdominal  cavity,  which  ends  at  the  lower 
portion  of  the  trunk  in  a  bony  basin  called  the  pelvis.     The 
two  latter  cavities  compose  the  trunk.     The  trunk  and  skull 
are    maintained    in    their    proper    relations    by   the   "  spinal 

The  transverse  section  shows  the  compact,  hard  outer  layer,  enclosing 
the  soft  pulp  or  marrow. 

The  longitudinal  section  shows,  at  its  upper  end,  the  layer  of  cartilage, 
its  thickness  and  intimate  connection  with  the  bone  ;  the  outer  layer  of 
bone  here  is  thinnest  and  gradually  increases  toward  the  middle  of  the 
shaft,  where  it  is  thickest ;  the  central  canal,  containing  the  marrow, 
becomes  smaller  as  it  approaches  the  head  of  the  bone,  where  it  is  lost  in 
the  dense  network  of  bony  structure.  The  latter  is  best  demonstrated  by 
holding  the  cut  surface  for  a  while  under  a  faucet,  so  as  to  wash  away  the 
blood,  etc.,  contained  in  the  meshes.  It  will  now  be  seen  that  these 
meshes  are  composed  of  delicate,  but  strong,  bony  partitions,  and 
arranged  in  such  angles  to  the  outer  wall  and  to  themselves  as  will  sup- 
port the  greatest  weight. 

7.  Bones,  why  curved  ?    8.  What  constitutes  the  skeleton  ? 


THE  FRAMEWORK  OF  THE  BODY  23 

column."  Branching  from  the  trunk  are  two  sets  of  limbs: 
the  arms,  which  are  attached  to  the  chest  by  means  of  the 
"collar-bone"  and  "shoulder-blade";  and  the  legs,  directly 
joined  to  the  lower  part  of  the  trunk. 


FIG.  5.  — BIBS  IN  A  NATURAL  AND  FIG.  6.  —  RIBS  SHOWING  THE  EFFECTS 

HEALTHY  STATE  OF  TIGHT  LACING 

9.  These  cavities  which  we  have  mentioned  are  designed 
for   the   lodgment   and   protection  of  the  more  delicate  and 
perishable  parts  of  the  system.     Thus,  the  skull,  together  with 
the  bones  of  the  face,  shelters  the  brain  and  the  organs  of 
four  senses,  —  sight,  hearing,  smell,  and  taste.    The  chest  holds 
the  heart,  lungs,  and  great  blood-vessels,  while  the  lower  part 
of  the  trunk  contains  the  liver,  stomach,  and  other  organs. 

10.  The  Joints.  —  The  point  of  union  of  two  or  more  bones 
forms  a  joint  or  articulation,  the  connection  being  made  in 
various  ways  according  to  the  kind  and  amount  of  motion 
desired.     The  movable  joints  are  connected  by  strong  fibrous 
bands,  called   ligaments.     These  ligaments  are   of  a  silvery 
whiteness,  and  very  unyielding;  so  much  so,  that  when  sudden 
violence  is  brought  to  bear  in  the  vicinity  of  a  joint,  the  bone 
to  which  a  ligament  is  attached  may  be  broken,  while  the 
ligament   itself  remains   uninjured.      When    this    connecting 
material  of  the  joints  is  strained  or  lacerated  by  an  accident,  a 
"  sprain  "  is  the  consequence.     An  injury  of  this  sort  may  be, 
and  frequently  is,  quite  as  serious  as  the  breaking  of  a  bone. 


9.  What  does  the  skull  shelter  *    10.  Describe  the  joints. 


24 


THE  FRAMEWORK  OF  THE  BODY 


11.  The  ligament,  then,  secures  firmness  to  the  joint;  it 
must 'also  have  flexibility  and  smoothness  of  motion.  This 
is  accomplished  by  a  beautiful  mechanism,  the  perfection  of 
which  is  only  feebly  imitated  by  the  most  ingenious  contriv- 
ance of  man.  The  ends  of  the  bones  are  covered  by  a  thin 
layer  of  cartilage  which,  being  smooth  and  elastic,  renders  all 
the  movements  of  the  joints  very  easy,  and  acts  as  a  cushion. 
Over  the  cartilage-  is  stretched  a  thin  membrane,  making  a 


FIG.  7.— THE  LIGAMENTS  OF  THE  WKIST 


FIG.  8.  —  CELLS  OF  CARTILAGE 


compressed  closed  sack.  This  is  called,  the  synovia!  mem- 
brane, and  is  constantly  moistened  by  a  colorless  liquid,  not 
unlike  the  white  of  egg  in  appearance  and  consistency,  whence 
its  name,  synovial  fluid  (synovia  =  egg-like). 

12.  Joints  are  classified  as  follows :  The  ball-and-socket 
joint,  which  has  the  greatest  freedom  of  motion,  and.  is  exem- 
plified by  the  hip  and  shoulder  joints ;  the  hinge  joint  as  shown 
by  the  elbow ;  and  the  gliding  joint,  where  the  motion  is  pro- 
duced by  one  surface  of  bone  gliding  over  another,  as  shown 
by'  the  wrist  and  ankle  joints.  The  junction  of  the  first  and 
second  vertebrae  forms  a  pivot  joint,  which  enables  the  head  to 
be  rotated  from  right  to  left.  The  bones  of  the  skull  are 
dove-tailed  together  by  what  are  termed  sutures. 


11.  Uses  of  ligaments  and  cartilage  ?    12.   How  are  joints  classified  ? 


THE  FRAMEWORK  OF  THE  BODY  25 


FIG.  9.  —  ELBOW-JOINT.    A,  Rone  of  the  arm  ;  B,  C,  Bones  of  the  forearm 

13.  The  Spinal  Column.  —  The  spinal  column  is  often  spoken 
of  as  "the  back  bone,"  whereas  in  reality  it  is  composed 
of  twenty-four  small  bones,  called  vertebrae.  These  unite  below 
with  the  sacrum,  which  forms  the  base  of  the  pelvis,  and  upon 
which  the  weight  of  the  ttody  rests;  joined  to  the  lower  end 
of  the  sacrum  is  a  small  bone  called  the  coccyx.  The  vertebrae 
are  divided  into  three  groups,  of  which  one  contains  the  seven 
cervical  vertebrae,  forming  the  neck,  another  the  twelve  dorsal, 
to  which  the  ribs  are  attached,  and  the  third  the  five  lumbar, 
forming  what  is  called  the  "  small  of  the  back." 

The  spinal  column  is  a  wonderful  piece  of  mechanism  It 
not  only  connects  the  important  cavities  of  the  body,  as  has 
already  been  shown,  but  also  itself  forms  a  canal,  which  con- 
tains the  spinal  cord.  The  joints  of  the  vertebrae  are  remark- 
able for  the  thick  layers  of  cartilage  which  separate  the 
adjacent  surfaces  of  bone.  The  amount  of  motion  between 
any  two  of  these  bones  is  not  great ;  but  these  little  move- 
ments, taken  together,  admit  of  very  considerable  flexibility, 
in  several  directions,  without  endangering  the  supporting 
power  of  the  column. 

J3.   Describe  the  spinal  column. 


26 


THE  FRAMEWORK  OF  THE  BODY 


14.    The  abundant  supply  of  inter-vertebral  cartilage  adds 
greatly  to  the  elasticity  of  the  frame.     It  is  due,  in  part,  to 
this  elastic  material  that  the  brain  and  other  delicate  organs 
are   not   more   frequently   injured   by   the   shock   of    sudden 
falls  or  missteps.     During  the  day,  the 
constant    pressure    upon    these   joints, 
while  the  body  is  erect,  diminishes  the 
thickness  of  the  cartilages;   so  that  a 
person  is  not  so  tall  in  the  evening  as 
in   the   morning.     The    effects   of  this 
compression  pass  away  when  the  body 
is  in  a  reclining  posture.     (Read  Note  3.) 
15.    Cartilage,  or   "gristle,"  consists 
of  round  or  oval  cells,  imbedded  in  a 
matrix,   or   base,   which   varies  in  the 
three  forms  of  cartilage  found  in  the 
human  body.     These  three  are,  1,  hya- 
line)  2j  white  Jibro-cartilage,  and  3,  yellow 
Jibro-cartilage. 

Hyaline  cartilage  is  that  found  on  the 
articular  ends  of  bone,  and  the  cartilages 
of  the  nose  and  larynx.  That  covering 
the  articular  ends  of  bones  serves  for 
the  purpose  of  forming  bone,  the  long 
bones  receiving  their  chief  growth  from 
the  cartilages  covering  both  ends. 

White  Jibro-cartilage  is  found,  among 
other  places,  in  the  disks  between  the 
vertebrae.  It  differs  from  hyaline  car- 
tilage chiefly  in  its  matrix,  which  is 
more  fibrous  in  character. 

Yellow  Jibro-cartilage  differs  from  the 
white  again  chiefly  in  the  structure  of 
its  matrix,  whose  fibres  are  found  in  greater  number  and 
density.  The  best  example  of  it  is  found  in  the  external  ear. 

3.  Some  Causes  of  Curvature  of  the  Spine.  —  "  Much  as  horse-riding 
is  valued  on  account  of  the  healthful  character  of  its  exercise,  yet  an  over- 
indulgence by  young  ladies  —  owing  to  the  oblique  position  in' which  the 

14.  Ya.lue  of  inter-vertebral  cartilage?    Structure?      10.  Wtyit  three  fonps  of  cartilage  ? 


Sacrum, 


Os  Coccygis 

FIG.  10.  —THE  SPINAL 
COLUMN 


THE  FRAMEWORK  OF  THE  KODY  27 

16.  The  Growth  of  Bone.  —  Bone,  like  all  the  other  tissues  of 
the  body,  is  constantly  undergoing  change,  old  material  being 
withdrawn,  to  make  room  for  a  fresh  supply.     This  change 
has  been  shown  conclusively  by  experiments.     If  an  animal  be 
fed  with  madder  —  a  red  coloring  matter — for  a  day  or  two, 
the  bones  soon  become  tinged ;  then,  if  the  madder  be  discon- 
tinued for  a  few  days,  the  original  color  returns.     If,  however, 
this  material  be  alternately  given  and  withheld,  at  short  inter- 
vals, the  bone  will  be  marked  by  a  succession  of  red  and  white 
rings.     In  very  young  animals,  all  the  bones  become  colored 
in  a  single  day  ;  in  older  ones,  a  longer  time  is  required.     The 
process  of  waste  and  repair,  therefore,  is  constantly  taking 
place  in  this  hard  substance,  and  with  astonishing  rapidity. 

17.  The  Repair  of  Bone. — Nature's   provision   for  uniting 
broken  bones  is  very  complete.     At  first,  blood  is  poured  out 

female  form  reyts  in  the  side-saddle  —  will  cause  the  spine  to  become 
curved."  To  avoid  this,  it  is  important  for  young  ladies  to  ride  occasion- 
ally on  the  opposite  side  of  the  horse.  Another  frequent  cause  of  curva- 
ture of  the  spine  is  the  use  of  the  sewing-machine,  especially  among  needy 
seamstresses,  whose  bread  frequently  depends  on  the  almost  unceasing 
labor  of  their  hands  and  feet,  while  sitting  in  a  constrained  position. 
Soon  after  croquet  became  a  favorite  amusement  among  the  fashionable 
young  ladies  of  England,  it  was  noticed  that  the  bent  position  assumed 
during  the  time  the  mallet  is  used,  caused  a  certain  deformity,  to  which 
was  given  the  name  of  the  "croquet  curvature."  The  use  of  high  heels 
on  boots  and  shoes  of  children,  by  throwing  the  weight  of  the  body  too  far 
forward,  on  the  front  of  the  foot,  and  destroying  the  natural  poise  of  the 
body,  acts  an  important  part  in  causing  the  spine  to  become  crooked. 
By  many  this  crooked  position  is  considered  to  be  largely  a  school-room 
disease,  for  the  reason  that  children  often  are  compelled  to  sit,  and  write 
or  study,  in  a  bent  posture  ;  but  there  must  be  other  causes  for  it,  since  it 
has  been  found  that  it  is  almost  exclusively  a  female  deformity.  Over 
eighty-four  per  cent,  of  the  cases  is  stated  by  one  writer  to  be  among 
girls.  But  inasmuch  as  the  majority  of  these  cases  begin  during  the 
years  of  schooling  —  from  the  ages  of  six  to  fourteen  —  great  attention 
should  be  paid  to  the  position  of  the  body  during  school  hours,  and  ample 
opportunity  should  be  offered,  by  a  regular  system  of  gymnastics,  to 
counteract  all  the  evil  influences  of  the  school-room  posture.  —  Heather- 
Bigg  on  Deformities  (in  part). 


16.  Change  in  bone?    Example  —  animal  and  madder.     Rapidity  of  change  in  color? 
Waste  and  repair  ? 

17.  How  is  a  broken  bone  united  ?    What  becomes  of  the  blood  caused  by  the  injury  ? 
What  takes  its  place  ?    How  long  does  it  usually  take  for  a  broken  bone  to  unite  t 


28  THE  FRAMEWORK  OF  THE  BODY 

around  the  ends  of  the  bone,  as  a  result  of  the  injury.  This  is 
gradually  absorbed,  and  gives  place  to  a  watery  fluid,  which, 
thickening  from  day  to  day,  acquires,  at  the  end  of  about  two 
weeks,  the  consistency  of  jelly.  This  continues  to  harden,  by 
the  deposit  of  new  bone-substance,  until,  usually  at  the  end  of 
five  or  six  weeks,  the  broken  bone  may  be  said  to  be  united. 
It  is,  however,  still  fragile,  and  must  be  used  carefully  a 
few  weeks  longer.  The  process  of  hardening  continues,  but 
months  must  pass  before  the  union  can  be  said  to  be  complete. 
(Read  Note  8.) 

18.  Changes  in  the  Skeleton. — Man  does  not  reach  his  full 
height  until  he  is  about  twenty-five  years  old;  and  even  after 
that  age,  the  bones  continue  to  increase  in  strength  and  hard- 
ness. Before  that  age  they  are  comparatively  soft  and  flexible, 
by  reason  of  the  gelatin  they  contain.  This  is  especially  true 
in  childhood ;  and  it  is  fortunate  that  it  is  so,  since  that  con- 
dition is  much  more  favorable  to  the  steady  and  rapid  growth 
of  the  bones  than  if  they  contained  more  of  the  lime,  as  is  the 
case  in  old  age,  when  there  is  no  occasion  for  change  in  the 
size  or  shape  of  the  skeleton.  The  skull,  however,  is  said  to 
increase  slightly  in  size,  even  in  advanced  life,  in  those  persons 
in  whom  the  brain  is  continually  employed  in  thought  or  study. 

4.  The  Management  of  a  Broken  Limb.  — "  Fractures'  are  usually 
met  with  when  the  person  is  dressed.  Therefore,  unless  there  is  bleeding, 
or  something  to  call  for  immediate  exposure  and  examination  of  the 
damaged  part,  do  not  be  in  a  hurry  to  remove  the  clothes.  If  the  arm  be 
hurt,  extemporize  a  sling  from  a  neck-handkerchief  or  some  other  article 
of  dress,  and  support  the  arm  from  elbow  to  wrist,  tying  the  ends  of  the 
handkerchief  in  a  knot  over  the  coat-collar  behind.  If  the  thigh  or  leg 
be  in  pain,  fasten  the  injured  limb  to  its  fellow  by  a  cravat  bandage  or 
two,  and  take  care  that  they  lie  side  by  side,  and  on  the  same  level ;  or 
fasten  outside  the  clothes  some  temporary  support  —  a  piece  or  two  of 
straight  stick,  with  a  bandage  —  and  then  remove  the  sufferer  quietly  and 
carefully  to  some  house  near  at  hand.  If  medical  aid  be  available,  send 
for  it  without  any  delay  ;  and  be  careful,  if  in  the  country,  and  so  at  some 
distance  from  the  doctor's  house,  to  forward  a  clear  statement  as  to  the 
apparent  nature  of  the  accident,  which  limb  is  hurt,  and  where  and  how 


18.  When  does  a  man  get  his  growth  ?  What  changes  then  take  place?  What  difference 
in  the  bones  of  a  child  and  those  of  a  man  ?  What  exception  in  case  of  the  skull  ?  Benefit 
in  flexibility  of  bones  ?  Cause  of  knock-knees  ?  Bow-legs? 


THE  FRAMEWORK  OF  THE  BODY  29 

However,  this  very  flexibility  of  the  bones,  in  early  life,  which 
favors  their  steady  growth  and  prevents  their  breaking  easily, 
is  sometimes  the  source  of  serious  deformity.  A  young  child 
may  be  allowed  to  stand  and  walk  too  early,  and,  as  a  conse- 
quence, the  lower  limbs  become  permanently  bent  inward,  in 
the  distortion  called  "knock-knees,"  or  outward,  as  in  "bow- 
legs."  For  the  same  reason,  a  bent  position  of  the  spinal 
column,  permitted  to  exist  habitually  in  childhood,  may  result 
in  a  life-long  deformity. 

19.  The  Erect  Posture.  —  Youth  is,  in  a  great  measure,  the 
forming  as  well  as  the  growing  period  of  the  frame.  Bad 
habits  of  posture,  early  formed,  become  fixed  in  later  life,  and 
their  results  —  as  seen  in  contracted  chests  and  round  shoulders 
—  are  with  difficulty  remedied.  Eight  habits,  on  the  other 
hand,  tend  to  produce  an  erectness  of  posture  which  is  favor- 
able, not  alone  to  strength  and  health,  but  also  to  grace  and 
ease.  The  following  directions  should  be  learned  and  prac- 
ticed: hold  the  head  erect  with  the  chin  somewhat  near  the 
neck;  expand  the  chest  in  front;  throw  the  shoulders  back, 
keeping  them  of  the  same  height  on  both  sides ;  maintain  the 
natural  curves  of  the  spine,  as  shown  in  the  last  figure.  Man 
alone,  of  all  the  animals,  has  the  power  to  stand  and  move  in 
the  erect  posture. 

it  happ^ned.  Let  this  statement,  too,  be  in  writing,  if  possible.  It  may 
well  happen,  however,  that  skilled  assistance  cannot  be  had,  and  in  this 
case  the  patient  should  be  undressed  quietly  and  cautiously.  It  will  be 
far  better  to  slit  up  the  dress  on  the  arm  or  leg  with  a  pair  of  scissors  than 
to  pull  it  off ;  but  however  the  covering  of  the  injury  may  be  managed,  it 
must  be  done  very  slowly  and  gently,  and  the  limb  should  be  supported 
so  as  to  prevent  jarring  and  shaking  to  the  damaged  part.  It  must  be 
carefully  kept,  too,  in  a  right  direction,  for  otherwise  some  sharp  splinter 
of  bone  may  penetrate  the  hitherto  unwounded  skin."  —  First  Help  in 
Accidents  and  Sickness. 


19.  What  is  the  forming  period  ?    Effects  of  bad  habits  of  posture  ?    Directions  for 
correct  posture  ? 


30 


THE  FRAMEWORK  OF  THE  BODY 


TOPICAL    OUTLINE 

1.  BONES  are  composed  of  mineral  substance  (lime)  two  parts,  and  animal 

substance  (gelatin)  one  part.    They  are  hard  on  the  surface,  and  light 
and  porous  in  the  interior. 
Uses.     a.   Framework  for  the  body. 

6.   Protection  for  delicate  organs, 
c.  Levers. 

2.  LIGAMENTS.   Strong  fibrous  bands. 

Use.   a.  Bind  bones  together. 

3.  CARTILAGE. 

Kinds,   a.  Hyaline. 

b.  White  fibre-elastic. 

c.  Yellow  fibro-elastic. 

Uses.     a.   Forms  strong  yet  flexible  frameworks. 

b.  Acts  as  buffers  in  deadening  shocks  and  blows. 

c.  Deepens  the  sockets  of  joints ;  example,  the  hip-joint. 

cl.  Covers  the  articulating   surfaces  of   bones,  thus  reducing 
friction. 

Immovable. Sutures,  —  skull. 

'  Gliding  joints,  —  ankle  and  wrist. 

4.  JOINTS.  -I  Ball-and-socket  joints,  — shoulder  and 

Perfect  -j         hip. 
Movable...  -I  Hinge  joints,  —  elbow  and  knee. 

Pivot  joints,  —  joint  of  atlas  and  axis. 
Imperfect Vertebrae  joints. 


QUESTIONS  FOR  TOPICAL  REVIEW 

•  PAGE 

1.  What  useful  purposes  do  the  bones  serve  ? 17, 18 

2.  State  what  you  can  of  the  composition  of  the  bones 18,  19 

3.  Of  the  usefulness  of  lime  in  the  bones 18 

4.  Of  the  usefulness  of  animal  substance  in  the  bones 19 

6.  State  what  you  can  of  the  structure  of  the  bones 19,  21 

6.  Of  the  strength  belonging  to  the  bones ' 21,  22 

7.  What  is  meant  by  the  human  skeleton  ? 22 

8.  Give  a  description  of  its  construction 23,  24 

9.  What  is  meant  by  a  joint  in  the  human  frame? 23 

10.  State  what  you  can  of  the  movable  joints 24 

11.  What  office  is  performed  by  the  ligaments  of  the  joints  ? 24 

12.  What  by  the  cartilage  at  the  joints  ? 25,  26 

13.  What  movable  joints  are  there  ? 24 

14.  Describe  the  construction  of  the  spinal  column 25 

15.  What  properties  and  powers  does  the  spinal  column  possess  ? 25 

16.  When  is  a  person  taller  than  at  other  times  ? 26 

17.  Give  the  reason  for  this 26 

18.  What  can  you  state  of  the  growth  of  bone  ? 27 

19.  Describe  the  process  by  which  a  broken  bone  is  repaired 27,  28 

20.  When  does  man  reach  his  full  height  ? 28 

21.  What  changes  in  the  bones  then  take  place  ? 28 

22.  Name  an  exception  to  the  general  rule 28 

23.  State  the  advantage  and  disadvantage  in  flexibility  of  bones 29 

24.  What  directions  are  given  for  the  correct  position  ? 29 


THE  FRAMEWORK  OF  THE  BODY 


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32 


THE  MUSCLES 


FIG.  11.—  THE  MUSCLES 


CHAPTER  II 

•  THE  MUSCLES 

The  Muscles — Structure — Flexion  and  Extension  —  The  Tendons —  Con- 
traction  —  Physical  Strength  —  Necessity  for  Exercise  —  Its  Effects  — 
Forms  of  Exercise  —  Walking  —  Riding  —  Gymnastics  —  Open-air 
Exercise  —  Effects  of  Exercise  —  Excessive  Exercise  —  Sleep  —  Rec- 
reation 

1.  The  Muscles. — The  great  mass  of  the  body  external  to 
the  skeleton  is  composed  of  the  flesh,  or  muscles,  which  largely 
determine  its  outline  and  weight.     The  nmscles  are  the  organs 
of  motion.     Their  number  is  over  five  hundred,  and  to  each 
of  them  is  assigned  a  separate  and  distinct  office.     They  have 
all  been  studied,  one  by  one,  and  a  name  given  to  each,  by 
the   anatomist.     They  differ  in  size   and   shape,  each  being 
exactly  fitted  for  its  peculiar  function.     Some  are  very  long 
and  slender;  others  are  short  and  thick.     (See  Fig.  11.)     The 
smallest  muscles  of  the  human  body  are  those  which  control 
the  bones  of  the  middle  ear.     Most  muscles  are  attached  to 
bones,  which   they  are   designed  to  move  or  hold  in  place. 
Such   muscles   are  called   skeletal  muscles.      Others,  like  the 
muscles  of  the  heart  and  stomach,  are  not  attached  to  bones ; 
they   carry   on  the  vital  processes,   and    are   called   visceral 
muscles. 

2.  Structure  of  Skeletal  Muscles.  —  If  we  examine  a  piece  of 
flesh,  we  observe  that  it  is  soft,  and  of  a'  deep  red  color.     It 
appears  to  be  composed  of  layers  and  bundles  of  small  fibres 
or  fasciculi.     The  whole  muscle  is  surrounded  by  a  loose  sheath 
of  connective  tissue,  called  the  perimysium.     From  this  main 
sheath  partitions  extend  and  envelop  each  bundle  of  fibres. 

1.  What  are  the  muscles  ?  Their  number  ?  The  design  of  most  of  them  ?  Skeletal 
muscles?  Visceral  muscles  ?  2.  The  structure  of  flesh  ?  Its  color,  etc.?  Of  what  is  flesh 
composed  ?  By  what  is  the  whole  muscle  surrounded  ? 


34 


THE  MUSCLES 


FIG.  12.  —  MUSCULAR  TISSUE 

a,  &,  Striped  muscular  fibres  ;  c,  The  same  more 
highly  magnified 


Most  skeletal  muscles  taper  at  one  or  both,  ends  until  the 
muscular  tissue  finally  disappears,  and  the  sheath  gradually 
changes  to  white,  fibrous,  inelastic  connective  tissue  which 
forms  tendons,  by  means  of  which  most  muscles  are  attached 
to  bone. 

3.  When  we  examine 
these  fibres  under  the  mi- 
croscope we  discover  that 
they  in  turn  are  made  up 
of  still  finer  fibres,  or  ft- 
brillce,  as'  shown  in  Fig. 
12.  The  fibres  are  beau- 
tifully marked  by  par- 
allel wavy  lines,  about 
ten  thousand  to  an  inch, 
which  give  the  fibre  its 
name  of  the  striped  mus- 
cular fibre.  All  of  the  voluntary  muscles  present  this  appear- 
ance. 

Striped  muscle  cells  are  from  one  to  one  and  one-half  inches 
in  length,  and  from  ^^  inch  to  ffa  inch  in  breadth.  These 
cells  lie  parallel  to  each  other  in  bundles.  All  action  of  the 
muscles  is  accomplished  by  changes  in  the  shape  of  these  cells, 
which  act  in  concert  under  the  control  of  the  nervous  system. 

When  these  cells  shorten  and  thicken,  the  whole  muscle 
undergoes  a  corresponding  change,  it  contracts ;  when  the  cells 
narrow  and  lengthen,  a  similar  change  occurs  in  the  shape  of 
the  whole  muscle,  it  relaxes.  Each  cell  is  encased  in  a  delicate 
membrane,  called  sarcolemma,  which  during  life  adheres  to  the 
protoplasm  within.  Each  cell  possesses  many  nuclei  which 
lie  just  under  the  sarcolemma.  Figure  12,  a,  shows  a  number  of 
these  adhering  fibrillae ;  &,  shows  these  bundles  torn  asunder 
(the  sarcolemma  is  visible  at  c)  ;  c,  shows  how  the  same  cells 
cleave  laterally  when  treated  with  chemicals  such  as  ammonium 
carbonate. 


3.  What  is  the  composition  of  the  fibres  ?  How  are  the  fibres  marked  ?  How  long  are 
the  striped  muscle  cells  ?  How  broad  ?  Describe  the  correspondence  between  action  of  the 
muscles  and  the  shape  of  the  cells. 


NOTE.— In  some  cases  illustrations  of  tissue  from  the  lower  animals  are  given  for 
the  reason  that,  while  the  tissue  is  the  same  as  that  of  man,  the  microscope  feveals  the 
structure  more  plainly. 


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TEASED  *  250. 

a.—  Muscular  fibre,  or  portion  of  one 
b.—  Fibrils. 


!*•*»* 


STRIPED  MUSCLE  OF  CRAB 
(EXTENDED),  STAINED 
WITH  H^MATOXYUN, 

TEASED  x  450. 

A. —  I/ight  stripe. 
,  B.—  Dark  stripe. 
C, — Intermediate  segment  in 
light  stripe. 


CARDIAC  MUSCLE  (HUMAN),  STAINED  WITH  H^MATOXYIJN  x  300. 


a.— Muscle  cells. 

b.—  Nuclei  of  satrie,  with  yellow  pigment  at  poles. 

c.—  Fibrous  tissue  between  muscle  fibres, 

d. —  Junctions  of  segments  of  muscle. 

e.—  Capillary  blooo-vessel. 


THE  MUSCLES  35 

4.  Structure  of  Unstriped  Muscle.  —  The   visceral   muscles, 
except  those  of  the  diaphragm  and  heart,  are  not  arranged 
in   definite  bundles,  nor  are  they  striped.     They  consist  of 
plain,  elongated  cells  which  taper  toward  the  ends.    -These 
cells  have  the  power  of  shortening  in  the  direction  of  their 
long  axes.     But  their  action  is   much   slower  than   that  of 
striped   muscular  cells.     Unstriped   muscles,   therefore,   con- 
tract with  a  slow,  vermicular  (worm-like)  motion.     Unstriped 
muscles  are  much  lighter  in  color  than  striped  muscles. 

5.  Heart  Muscle.  —  This  muscle  is  dark  in  color,  like  skeletal 
muscles.     Its  action  is  entirely  beyond  the  control  of  the  will. 
The  histology  of  heart  muscle  closely  resembles  that  of  skeletal 
muscles.     Its  cells  are  striped,  but  they  are  much  smaller  than 
the  cells  of  skeletal  muscles ;  they  usually  contain  only  one 
nucleus,  and  their  ends   are  branched.     These   branches   fit 
closely  into  one  another. 

6.  Flexion  and  Extension.  —  The  muscles  are,  for  the  most 
part,  so  arranged  in  pairs,  or  corresponding  sets,  that  when 
motion  is  produced  in  one  direction  by  one  set,  there  is,  oppo- 
site to  it,  another  muscle,  or  group  of  muscles,  which  brings 
the  limb  back  to  its  place.     When  they  act  alternately,  a  to- 
and-fro  movement  results.     When  a  joint  is  bent,  the  motion 
is  called  flexion  ;  and  when  it  is  made  straight  again,  it  is 
called  extension.    WThen  both  sets  act  equally  and  at  the  same 


PIG.  13.  — RAISING  THE  FOREARM.    A,  Biceps  muscle 

moment,  no  motion  is  produced,  but  the  body  or  limb  is  main- 
tained in  a  fixed  position:  this  occurs  when  we  stand  erect. 

4.  How  do  visceral  muscles  differ  from  skeletal  muscles  ?    5.  Describe  the  heart  muscle, 
6.   What  is  flexion  ?    Extension? 


36  THE  MUSCLES 

The  muscles  which  produce  extension  are  more  powenul  than 
those  opposite  to  them.  Muscles  which  flex  are  called  flexors; 
those  which  straighten  are  called  extensors.  Other  muscles 
draw  the  limbs  away  from  the  axis  of  the  body,  and  are  called 
abductors.  These  are  opposed  by  muscles  whose  action  brings 
the  limb  back  toward  the  axes  of  the  body ;  such  are,  in  con- 
sequence, called  adductors.  In  general,  the  skeletal  muscles 
are  paired  in  the  manner  just  described ;  when  one  contracts, 
its  mate  must  relax,  and  vice  versa.  This  arrangement  is 
commonly  called  antagonistic. 

7.  The  muscles  are  also  distinguished  as  the  voluntary  and 
involuntary  muscles,  according  as  they  are,  or  are  not,  under 
the  control  of  the  will.     The  heart  is  an  example  of  the  invol- 
untary variety.     We  cannot  change  its  action  in  the  least  by 
an  effort  of  the  will.     When  we  sleep,  and  the  will  ceases  to 
act,  the  heart  continues  to  beat  without  cessation.     The  volun- 
tary muscles,  on  the  other  hand,  are  such  as  are  used  only 
when  we  wish  or  will  to  use  them  —  as  the  muscles  of  the  hand 
or  arm  (Figs.  13  and  14).     (Read  Note  1.) 

8.  The  Tendons.  —  Tendons,  or  sinews,  are  the  extremities 
of  muscles,  and  are  firmly  fastened  upon  the  bone.     They  are 
very  strong,  and  of  a  silvery  whiteness.     They  may  be  felt  just 
beneath  the  skin,  in  certain  parts  of  the  body,  when  the  muscles 
are  being  used,  as  at  the  bend  of  the  elbow  or  knee.      The 
largest  tendon  of  the  body  is  that  which  is   inserted  into 
the  heel,  called  the  tendon  of  Achilles,  after  the  hero  of  the 
Grecian  poet,  the  fable  relating  that  it  was  at  this  point  that 
he  received  his  death-wound,  no  other  part  of  his  body  being 

1.  The  Perfection  of  the  Human  Hand.  —  "  Gordy  counts  thirty-four 
distinct  movements  of  the  hand,  and  if  we  include  the  combinations  of 
these  different  movements,  we  shall  reach  a  much  higher  number.  Prop- 
erly speaking,  the  hand  belongs  to  man  alone,  and  its  form  does  not  per- 
mit us  to  consider  it  an  organ  of  locomotion,  as  is  the  case  with  certain 
animals  most  closely  resembling  man.  Nothing  gives  a  more  complete 
idea  of  the  perfection  of  the  mechanism  of  the  hand  than  the  execution  of 
instrumental  music.  Examine  an  artist  while  he  plays  the  violin.  His 
fingers  rest  upon  the  strings  so  as  to  leave  them  exactly  of  the  length 


7.  Describe  the  voluntary  and  involuntary  muscles,  and  give  examples  of  each.    8.  De- 
scribe the  tendons.    Mention  one. 


THE  MUSCLES 


37 


r> 


FIG.  14  shows  the  muscles  and  tendons  of  the  hand  ;  A  showing  the  palm,  B  the  back  of  the 
hand.  These  numerous  muscles  and  tendons  form  a  very  complicated  piece  of  mecha- 
nism, and  help  to  give  to  the  hand  its  marvellous  dexterity  and  flexibility.  Over  certain 
joints,  such  as  the  wrist  and  ankle,  ligaments  in  broad  bands,  as  seen  in  Fig.  14,  B,  C, 
are  bound.  They  keep  the  tendons  in  place. 

vulnerable  (Fig.  15).  The  muscles  in  the 
front  part  of  the  thigh  unite  to  form  a  sin- 
gle and  very  powerful  tendon,  and  enclose 
a  small  bone  called  the  knee-pan,  which, 
acting  like  a  pulley,  greatly  increases 
their  power,  and  at  the  same  time  protects 
the  front  of  the  knee-joint  (Fig.  16). 

9.  Muscular  Contraction.  — The  muscles, 
when  acted  upon  by  the  appropriate  stim- 
ulus, contract,  or  so  change  their  shape, 
that  their  extremities  are  brought  nearer 
together.  The  bending  of  the  arm,  or  of 
a  finger,  is  effected  in  this  manner,  by  the 
will ;  but  the  will  is  not  the  only  means 
of  producing  this  effect.  Electricity,  a 
sharp  blow  over  a  muscle,  and  other  stim- 
uli, also  cause  it.  Contraction  does  not 


Fiu.  15 
LOWER  PORTION  OP  THE  LEO 


9.   What  are  the  causes  of  muscular  contraction  ? 


38 


THE  MUSCLES 


always  cease  with  life.  In  man,  after  death  from  cholera, 
automatic  movements  of  hands  and  feet  have  been  observed, 
lasting  not  less  than  an  hour.  In  certain  cold-blooded  animals, 
as  the  turtle,  contraction  has  been  known  to  take  place  for 
several  days  after  the  head  has  been  cut  off. 

10.  The  property  which,  in  muscle,  enables  these  movements 
to  take  place  is  called  contractility.  If  we  grasp  a  muscle  while 
in  exercise  (for  example,  the  large  muscle  in  the  front  of  the 


FIG.  16.  —  VIEW  OF  KNEE-JOINT.     A,  Thigh-bone ;  B,  Knee-pan  ;  C,  D,  Leg-bones 

arm),  we  notice  the  alternate  swelling  and  decrease  of  the 
muscle,  as  we  move  the  forearm  to  and  fro.  It  was  at  one 
time  supposed  that  the  muscle  actually  increased  in  volume 
during  contraction.  This,  however,  is  not  the  case ;  for  the 


necessary  for  the  tones  they  are  to  give.  The  half  of  a  millimetre,  more 
or  less,  greatly  changes  the  accuracy  of  the  note  ;  and  a  chord  a  milli- 
metre out  of  place  produces  a  note  which  even  the  unpractised  ear  can 
recognize  as  false.  But  the  fingers  fall  upon  the  strings  at  precisely  the 
point  required.  They  run  over  them,  succeeding  each  other  with  giddy 


10.  What  is  contractility  ?    How  may  the  contractility  of  muscles  be  seen  ? 


THE  MUSCLES  39 

muscle,  while  gaining  in  thickness,  loses  in  length  in  the  same 
proportion;  and  thus  the  volume  remains  the  same  in  action 
and  at  rest. 

11.  Contraction  is  not  the  permanent,  or  normal  state  of  a 
muscle.  It  cannot  long  remain  contracted,  but  after  a  time  it 
wearies,  and  is  obliged  to  relax.  After  a  short  rest  it  can  then 
again  contract.'  It  is  for  this  reason  that  the  heart  can  beat 
all  through  life,  night  and  day,  by  having,  as  we  shall  here- 
after see,  a  brief  interval  of  rest  between  successive  contrac- 
tions. For  the  same  reason,  it  is  more  fatiguing  to  stand  for 
any  great  length  of  time  in  one  position,  than  to  be  walking 
for  the  same  period.  Intimately  associated  with  muscular 
tissue  in  all  parts  of  the  body  is  more  or  less  fat,  or  adipose 
tissue.  It  is  especially  abundant  directly  under  the  skin,  to 
which  it  gives  an  appearance  of  plumpness  and  smoothness. 
In  prolonged  illness,  where  emaciation  is  the  result,  the  body 
uses  the  stored-up  fat  for  nourishment.  Fat  also  gives  symme- 
try to  the  body,  serves  as  cushions,  and  protects  from  sudden 
changes  of  temperature.  The  histology  of  adipose  tissue  shows 
that  the  fat  cells  are  very  simple  in  construction.  They  are 
usually  round  or  oval  in  shape,  possessing  a  cell  wall,  enclos- 
ing a  globule  of  fat.  The  nucleus  of  the  cell  from  which  it 

rapidity,  following  every  imaginable  combination,  and  yet  the  hand  gliding 
over  the  instrument  incessantly  changes  its  position.  Sometimes  a  single 
finger  produces  an  isolated  note ;  sometimes  two  or  three  act  simultane- 
ously to  produce  a  concord  ;  while  a  fourth,  striking  a  string  with  increas- 
ing rapidity,  produces  a  trill  which  rivals  the  nightingale.  Add  to  all 
these  the  modifications  necessary  to  swell  the  sound  or  let  it  die  away  — 
all,  in  a  word,  that  constitutes  musical  expression  —  and  it  will  be  admitted 
that  this  mechanism  is  allied  to  the  wonderful,  and  that  it  surpasses  the 
most  perfect  productions  of  human  art."  A  further  idea  of  the  rapidity 
of  the  hand's  movements  is  given  in  the  playing  of  a  skilful  pianist,  whose 
hands,  oftenest  occupied  together,  produce  on  an  average  six  to  eight 
notes  at  a  time,  or  about  640  notes  in  a  minute  in  medium  time,  and  960 
notes  in  extremely  quick  time.  —  The  Wonders  of  the  Human  Body. 


11.  Is  contraction  the  normal  state  of  the  muscle  ?  Can  this  state  be  permanently 
maintained  ?  How  is  the  beating  of  the  heart  maintained  ?  Why  is  it  more  fatiguing  to 
stand  for  any  great  length  of  time  in  one  position,  than  to  be  walking  for  the  same  period  ? 
What  is  adipose  tissue  f  What  purposes  does  it  serve  ?  Describe  the  structure  of  fat 


40  THE  MUSCLES 

was  developed  remains  in  a  flattened  form,  surrounded  by  a 
small  amount  of  the  original  protoplasm  at  one  side  of  the  cel!7 
between  the  oil  globule  and  the  cell  wall. 

12.  Relative  Strength  of  Animals.  —  The  amount  of  muscular 
power  which  different  animals  can  exert,  has  been  tested  by 
experiment.     By  determining  the  number  of  pounds  which  an 
animal  can  drag  upon  a  level  surface,  and  afterward  comparing 
that  with  its  own  weight,  we  can  judge  of  its  muscular  force. 
It  is  found  that  man  is  able  to  drag  a  little  less  than  his  own 
weight.     A  draught-horse  can  exert  a  force  equal  to  about 
two-thirds  of  his  weight.     The  horse,  therefore,  though  much 
heavier  than  man,  is  relatively  not  so  powerful. 

13.  Insects   are   remarkable  for  their   power  of   carrying 
objects  larger  and  heavier  than  themselves.     Many  of  them 
can  drag  ten,  and  even  twenty  times  their  weight.     Some  of 
the  beetles  have  been  known  to  move  bodies  more  than  forty 
times  their  own  weight.     So  far,  therefore,  from  it  being  a  fact 
that  animals  have  strength  in  proportion  to  their  weight  and 
bulk,  the  reverse  of  that  statement  seems  to  be  the  law. 

14.  Physical  Strength.  —  The  difference  in  strength,  as  seen 
in  different  individuals,  is  not  due  to  any  original  difference  in 
their  muscles.     Nature  gives  essentially  the  same  kind  and 
amount  of  muscles  to  every  healthy  person,  and  the  power  of 
one,  or  the  weakness  of  another,  arises,  in  great  part,  from  the 
manner  in  which  these  organs  are  used  or  disused. 

15.  Many  authors  complain  of  the  physical  degeneracy  of 
men  at  the  present  day,  as  compared  with  past  generations. 
There  is  room  for  doubt  as  to  the  correctness  of  this  statement. 
Certain  experiments  have  recently  been  made  with  the  metallic 
armor  worn  seven  hundred  years  ago,  by  which  it  is  found  that 
any  man,  of  ordinary  height  and  muscular  development,  can 
carry  the  armor  and  wield  the  weapons  of  an  age  supposed  to 

12.  Muscular  power  of  animals  ?    How  tested?    Man's  power?    Horse's?    The  com- 
parison ? 

13.  Power  of  insects  ?    Beetles  ?    Give  the  conclusion. 

14.  Difference  in  strength  of  individuals  ?    How  caused  ? 

15.  Complaint  in  relation  to  degeneracy?     How  true?     How  determined  by  armor? 
The  fair  supposition. 


THE   MUSCLES  41 

be  greatly  our  superior  in  strength.  When  we  consider  that  in 
those  days  only  very  strong  men  could  endure  the  hardships  of 
soldier-life,  it  is  fair  to  suppose  that  our  age  has  not  so  greatly 
degenerated  in  respect  to  physical  strength. 

16.  Importance  of  Exercise.  —  Action  is  the  law  of  the  living 
body.     Every  organ  demands  use  to  preserve  it  in  full  vigor, 
and  to  obtain  from  it  its  best  services.     The  value  of  that 
training  of  the  mind,  which  we  call  education,  is  everywhere 
recognized.     The  child  is  early  put  to  school,  and  for  many 
years  continues  to  study,  in  order  that  his  brain,  which  is  the 
great  centre  of  mental  power,  may  act  healthfully  and  power- 
fully.    It  is  important  that  the  muscles,  also,  should  receive 
their  education  by  exercise.     This  is  true,  not  only  in  respect 
to  children,  but  also  of  adults  whose  occupation  confines  them 
within  doors,  and  requires  chiefly  brain-work. 

17.  Persons  who  are  engaged  in  manual  labor  in  the  open 
air  obtain  all  the  exercise  necessary  for  bodily  health  in  their 
regular  business :  their  need  is  more  likely  to  be  a  discipline 
or  exercise  of  the  mind.     A  perfect  business  of  life,  therefore, 
would  be  one  which  would  combine  both  physical  and  mental 
labor  in  their  proper  proportions.     If  such  a  business  were 
possible  for  all  the  human  race,  life  would  thereby  be  vastly 
prolonged.     Such,  in  fact,  is  to  a  large  extent  the  occupation 
pertaining  to  one  period  of  life  —  childhood.     One  part  of  the 
time  is  given  to  study,  and  another  to  muscular  education  by 
means  of  games  and  sports.     The  restlessness  and  playfulness 
of  children  is  not  only  natural  but  beneficial. 

18.  The  Effects  of  Exercise.  —  Exercise  consists  in  a  well- 
regulated  use  of  the  voluntary  muscular  system.     The  effects, 
however,  are  not  limited  to  the  parts  used.     Other  organs, 
which  are  not  under  the  control  of  the  will,  are  indirectly 
influenced  by  it.     The  heart  beats  more  rapidly,  the  skin  acts 
more  freely,  the  temperature  rises,  the  brain  is  invigorated, 

16.  Action  ?    Use  of  organs  ?    Training  of  the  mind  ?    The  child's  brain  ?    Education 
of  the  body  ? 

17.  Work  in  the  open  air  ?    A  perfect  business  ?    The  consequence  of  universal  perfect 
business  ?    Occupation  of  children  ? 

18.  In  what  does  exercise  consist  ?    Effects  of  it  ? 


42  THE  MUSCLES 

and  the  appetite  and  power  of  digestion  are  increased.  An 
increased  exhalation  from  the  lungs  and  skin  purifies  the  cur- 
rent of  the  circulation,  and  the  body  as  a  whole  thrives  under 
its  influence.  (Head  Note  2.) 

19.  The  first  effects   of  exercise,   however,  are  upon  the 
muscles  themselves ;  for  by  use  they  become  rounded  out  and 
firm,  and  increase  in  power.     If  we  examine  a  muscle  thus 
improved  by  exercise,  we  find  that  its  fibres   have   become 
larger  and  more  closely  blended  together,  that  its  color  is  of  a 
darker  red,  and  that  the  supply  of  blood-vessels  has  increased. 
Without  exercise  the  muscle  appears  thin,  flabby,  and  pale. 
On  the  other  hand,  excessive  exercise,  without  sufficient  relax- 
ation, produces  in  the  muscle  a  condition  not  very  different 
from   that  which  follows   disuse.     The  muscle   is  worn  out 
faster  than  nature  builds  it  up,  and  it  becomes  flabby,  pale, 
and  weak. 

20.  Violent  exercise  is  not  beneficial ;  and  spasmodic  efforts 
to  increase  the  muscular  strength  are  not  calculated  to  secure 
such  a  result.     Strength  is  the  result  of  a  gradual  growth,  and 
is  most  surely  acquired  if  the  exercise  be  carried  to  a  point 
short  of  fatigue,  and  after  an  adequate  interval  of  rest.     To 
gain  the  most  beneficial  results,  the  exercise  should  be  at  regu- 

2.  Health  in  Athletic  Exercise.  —  "Health  is  perpetual  youth  —  that 
is,  a  state  of  positive  health.  Merely  negative  health,  the  mere  keeping 
out  of  the  hospital  for  a  number  of  years,  is  not  health.  Health  is  to  feel 
the  body  a  luxury,  as  every  vigorous  child  does  ;  as  the  bird  does  when 
it  shoots  and  quivers  through  the  air,  not  flying  for  the  sake  of  the  goal, 
but  for  the  sake  of  flight ;  as  the  dog  does  when  he  scours  madly  across 
the  meadows,  or  plunges  into  the  muddy  blissfulness  of  the  stream  ;  but 
neither  bird,  nor  dog,  nor  child  enjoys  his  cup  of  physical  happiness  — 
let  the  dull  or  the  worldly  say  what  they  will  —  with  a  felicity  so  cordial 
as  the  educated  palate  of  conscious  manhood.  To  '  feel  one's  life  in  every 
limb,'  this  is  the  secret  bliss  of  which  all  forms  of  athletic  exercise  are 
merely  varying  disguises  ;  and  it  is  absurd  to  say  that  we  cannot  possess 
this  when  character  is  mature,  but  only  when  it  is  half  developed.  As 
the  flower  is  better  than  the  bud,  so  should  the  fruit  be  better  than  the 
flower."  

19.  General  effect  upon  the  muscles?    Special  effect  ?    E  ffects  of  inaction  ?    Of  excessive 
exercise  ? 

20.  Of  violent  and  spasmodic  efforts  ?    Strength,  how  attained  ?    Give  the  particulars. 


NOTK-IH  some  cases  illustrations  of  tissue  from  the  lower  animals  are  given  for 
the  reason  that,  while  the  tissue  Is  the  same  as  that  of  man,  the  microscope  reveals  the 
structure  more  plainly. 


NON-STRIf  ED  MUSCLE  CELLS,  STAINED  WITH 

a.— Dissociated  cells  from  intestine  of  cat  x  500. 

b.—  Muscle  cells  of  external  muscular  coat  of  intestine  of  cat  x  300. 

c.— Middle  part  of  isolated  cell,  under  a  higher  power. 


OF  SALAMANDER,  STAINED  WITH  H2BMATOXYLIN 

AND  EOSIN  r  300. 
a. —  Non-striped  muscle  cells. 
*.—  Tri-radiate  cell. 

c. —  Blood  capillary  containing  altered  corpuscles. 
</.—  Connective  tissue  cell  of  bladder  wall. 


x       THE  MUSCLES  43 

lar  hours  and  during  a  regular  period,  the  activity  and  the  time 
varying  with  the  strength  of  the  individual,  and  carefully 
measured  by  it.  (Read  Note  3.) 

21.  Different  Modes  of  Exercise.  —  There  are  very  few  who 
have  not  the  power  to  walk.     There  is  required  for  it  no 
expensive  apparatus,  nor  does  it  demand  a  period  of  prelimi- 
nary training.     Walking  may  be  called  the  universal  exercise. 
With  certain  foreign  nations,  the  English  especially,  it  is  a 
very  popular  exercise,  and  is  practised  habitually  by  almost 
every  class  of  society ;  by  the  wealthy  who  have  carriages,  as 
well  as  by  those  who  have  none ;  by  women  as  well  as  by  men. 

22.  Eunning,  leaping,  and  certain  other  more  rapid  and 
violent  movements  are  the  forms  of  exercise  that  are  most 
enjoyed  in  childhood.     For  the  child,  they  are  not  too  severe, 
but  they  maybe  so  prolonged  as  to  become  injurious.  Instances 
have  been  recorded  where  sudden  death  has  resulted  after 
violent  playing,  from  overtaxing  the  heart:  for  example,  we 
have  the  case  of  a  young  girl  who,  while  skipping  the  rope, 

3.  The  Hi-effects  of  Over-exertion.  —  "It  should  be  recollected  that 
the  action  of  the  muscles  has  limits,  as  well  as  that  of  every  other  organ 
of  the  body.  The  muscles  and  the  heart  may  be  taxed  too  severely,  and 
permanent  derangements  may  be  produced  by  overtaxing  the  human 
body.  The  ancient  gymnasts  among  the  Greeks  are  said  to  have  become 
prematurely  old,  and  the  clowns  (or  acrobats)  and  athletes  of  our  own 
days  suffer  from  the  severe  strain  put  upon  their  muscular  systems."  The 
effects  of  boat-racing  in  England  have  been  thus  described  by  Dr.  Skey, 
-an  eminent  surgeon :  "  The  men  look  utterly  exhausted.  Their  white 
and  sunken  features  and  pallid  lips  show  serious  congestion  of  the  heart 
and  lungs,  and  the  air  of  weakness  and  lassitude  makes  it  a  marvel  how 
such  great  exertion  should  have  been  so  nobly  undergone.  We  have 
repeatedly  seen  the  after  ill-effects  —  spitting  of  blood,  congested  lungs, 
and  weakness  of  the  heart  from  over-distension."  "Persons  should 
neither  walk,  run,  leap,  or  play  at  any  game,  to  the  extent  of  producing 
permanent  or  painful  exhaustion.  All  exercise  should  be  attended  with 
pleasurable  feelings  ;  and  when  pain  is  produced  by  proper  exercise,  those 
who  suffer  should  rather  seek  medical  advice  than  persevere  in  exercise." 
— Lankester's  Manual  of  Health. 


21.  What  may  walking  be  called  ?    What  further  is  said  of  walking  ? 

22.  What  is  said  of  running,  and  other  like  movements  ?   What,  as  related  to  childhood  ? 
What  instances  are  alluded  to  ?    Example  ? 


44  THE   MUSCLES 

and  endeavoring  to  excel  her  playmates  by  jumping  the  great- 
est number  of  times,  fell  dead  from  rupture  of  the  heart. 

23.  Carriage-riding  is  particularly  well  suited  to  invalids 
and  persons  advanced  in  life.     Horseback  exercise  brings  into 
use  a  greater  number  of  muscles  than  any  other  one  exercise, 
and  with  it  there  is  an  exhilaration  of  feeling  which  refreshes 
the  mind  at  the  same  time.     It  is  one.  of  the  manliest  of  exer- 
cises, but  not  less  suitable  for  women  than  for  men.     To  be 
skilful  in  riding,  it  should  be  begun  in  youth. 

24.  For  those  who  live  neai   streams  or  bodies  of  water, 
there  are  the  delightful  recreations  of  boating,  swimming,  and 
skating.    Certain  of  these  exercises  have  a  practical  importance 
aside  from  and  above  their  use  in  increasing  the  physical  vigor. 
This  is  especially  true  of  boating  and  swimming,  since  they  are 
often  the  means  of  saving  life.     Practice  in  these  exercises 
also  teaches  .self-reliance,    courage,   and  presence/  of    mind. 
Persons  who  have  become  proficient  in  these  vigorous  exercises 
are  generally  the  ones  who,  in  times  of  danger,  are  the  quickest 
to  act  and  the  most  certain  to  do  so  with  judgment. 

25.  Physical  Culture.  — That  form  of  exercise  which  interests 
and  excites  the  mind,  will  yield  the  best  results ;  but  to  some 
persons  no  kind  of  exertion  whatever  is,  at  first,  agreeable. 
They  should,  nevertheless,  make  a  trial  of  some  exercise,  in 
the  expectation  that,  as  they  become  proficient  in  it,  it  will 
become  more  pleasant.     In  exercise,  as  many  sets  of  muscles 
should  be  employed  as  possible,  open-air  exercise  being  the 
best.     Parlor  gymnastics  and  the  discipline  of  the  gymnasium 
are  desirable,  but  they  should  not  be  the  sole  reliance  for 
physical  culture.     No  in-door  exercise,  however  excellent  in 
itself,  can  fill  the  place  of  hearty  and  vigorous  activity  in  the 
open  air.     (Read  Note  4.) 

4.  Exercise  should  be  Pleasurable.  —  "  The  world  seldom  attaches 
much  value  to  things  which  are  plain  and  easily  understood.  The  dervish 
in  the  Eastern  allegory,  well  aware  of  this  weakness,  knew  that  it  would 
be  in  vain  to  recommend  the  sultan,  for  the  cure  of  his  disease,  simply  to 


23.  Carriage-riding?    Horseback-riding? 

24.  Boating,  swimming,  and  skating  ? 

25.  What  kind  of  exercise  yields  the  best  results?    What  advice  is  given  ? 


THE  MUSCLES  45 

W  Excessive  Exercises. — If  neglect  of  exercise  is  injurious, 
so  also  is  the  excess  of  it.  Violent  exertions  do  harm ;  they 
often  cause  undue  strain,  and  even  lasting  injury  to  some  part 
of  the  body.  For  this  reason  the  spirit  of  rivalry  which  leads 
to  tests  of  endurance  and  feats  of  strength  should  be  dis- 
couraged. Those  trials  of  the  muscles,  especially,  which  are 
supposed  to  demand  "training,"  should  not  be  encouraged. 
Training,  it  is  true,  can  produce  a  remarkable  muscular  develop- 
ment, so  that  nearly  every  muscle  of  the  limbs  is  as  large  and 
corded  as  the  arm  of  a  blacksmith ;  but  it  is  too  often  at  the 
expense  of  some  internal,  vital  organ.  Large  muscles  are  not 
a  certain  index  of  good  health.  It  was  well  known  by  the 
ancients  that  athletes  of  their  day  were  short-lived,  notwith- 
standing the  perfection  of  the  physical  training  then  employed. 
When  a  person  overtasks  the  heart,  or,  in  other  words,  "  gets 
out  of  breath,"  he  should  regard  it  as  a  signal  to.  take  rest.  It 
is  well  known  that  both  horses  and  men,  after  having  been 
brought  into  "  condition "  for  competitive  trials,  soon  lose  the 
advantages  of  their  training  after  the  occasion  for  it  has 


27.  Gymnastic  Exercises  for  Schools  and  Colleges.  —  In  the 
system  of  education  among  the  ancients,  physical  culture  pre- 
dominated. In  ancient  Greece,  physical  exercises  in  schools 
were  prescribed  and  regulated  by  law,  and  hence  these  schools 
were  called  gymnasia.  At  the  present  time,  on  the  contrary, 
this  culture  is  almost  wholly  unknown,  as  a  part  of  the  course 
of  education,  in  our  schools,  and  but  to  a  limited  extent  in 

take  exercise.  He  knew  that  mankind  in  general  required  to  be  cheated, 
gulled,  cajoled,  even  into  doing  that  which  is  to  benefit  themselves.  He 
did  not,  therefore,  tell  the  sultan,  who  consulted  him,  to  take  exercise,  but 
he  said  to  him :  4  Here  is  a  ball,  which  I  have  stuffed  with  certain  rare, 
costly,  and  precious  medicinal  herbs.  Your  highness  must  take  this  bat, 
and  with  it  beat  about  this  ball  until  you  perspire  very  freely.  You  must 
do  this  every  day.1  His  highness  did  so,  and  in  a  short  time  the  exercise 
of  playing  at  bat  and  ball  with  the  dervish  cured  his  malady." — First  Help. 


26.  Physical  culture  among  the  ancients  ?    In  Greece  ?    In  schools  and  colleges  at  the 
present  time  ?    Result  to  the  body  and  mind  ? 

27.  The  result  of  gymnastics  in  our  colleges  and  other  institutions  of  learning  ? 


46  THE  MUSCLES 

colleges.  In  a  few  of  our  schools,  however,  physical  exercises 
have  been  introduced,  with  manifest  advantage  to  the  students, 
and-  they  form  a  part  of  the  regular  curriculum  of  exercises,  — 
as  much  so  as  the  recitations  in  geography,  grammar,  or  Greek. 
The  good  effect  of  the  experiments,  as  shown  in  improved 
scholarship  as  well  as  increased  bodily  vigor,  in  the  institutions 
where  the  plan  has  been  tried,  will,  it  is  hoped,  lead  to.  its 
universal  adoption.  We  should  then  hear  less  frequently  of 
parents  being  obliged  to  withdraw  their  children  from  school, 
because  they  become  exhausted  or,  perchance,  have  lost  their 
health  from  intense  and  protracted  mental  application. 

28.  Were  gymnastics  more  common  in  our  educational  insti- 
tutions, we  should  not  so  often  witness  the  sad  spectacle  of 
young  men  and  women  leaving  our  colleges  and  seminaries, 
with  finished  educations  it  may  be,  but  with  constitutions  so 
impaired  that  the  life  which  should  be  devoted  to  the  accom- 
plishment of  noble  purposes  must  be  spent  in  search  of  health. 
Spinal  curvatures,  which,  according  to  the  experience  of  phy- 
sicians, are  now  extremely  frequent,  especially  among  women, 
would  give  place  to  the  steady  gait  and  erect  carriage  which 
God  designed  his  human  creatures  should  maintain.  (Head 
Notes  5  and  6.) 

5.  Health  and  Strength  are  not  always  Identical.  —  "  Health  and 
strength  are  not  synonymous  terms.  A  person  may  have  great  strength 
in  his  limbs,  or  in  certain  muscles  about  the  body,  but  really  not  have 
good  health.  It  is  altogether  a  mistaken  idea  to  suppose  that  physical 
exercises  have  for  their  sole  object  the  attainment  of  strength.  There 
are  other  tissues  and  organs  in  the  human  system  besides  the  muscular  ; 
and  the  healthy  action  of  the  lungs  and  the  stomach  is  far  more  important 
than  great  strength  in  the  arms,  legs,  or  the  back.  It  is  here,  in  this 
general  exercise  of  all  the  muscles  and  parts  of  the  body,  that  a  well- 
regulated  system  of  gymnastics  has  its  great  excellence.  It  aims  to  pro- 
duce just  that  development  of  the  human  system  upon  which  good  health 
is  permanently  based,  described  by  a  distinguished  writer  as  follows :  — 
*  Health  is  the  uniform  and  regular  performance  of  all  the  functions  of 
the  body,  arising  from  the  harmonious  action  of  all  its  parts,'  —  a  physical 
condition  implying  that  all  are  sound,  well-fitting,  and  well-matched. 
Some  minds  do  not  look  far  enough  into  life  to  see  this  distinction,  or  to 
value  it  if  seen ;  they  fix  their  eyes  longingly  upon  strength — upon  strength 


28.  Were  gymnastics  more  common  ?    To  what  are  spinal  curvatures  due  ? 


THE  MUSCLES  47 

29.  All  the  exercises  necessary  for  the  proper  development 
of  the  body  may  be  obtained  from  the  use  of  a  few  simple  con- 
trivances, that  every  one  can  have  at  home  at  little  cost  —  less 
by  far  than  that  of  useless  toys.     Many  of  these  may  be  made 
available  in  the  parlor  or  chamber,  though  all  exercises  are  far 
more  useful  in  the  open  air.     A  small  portion  of  the  day  thus 
spent  will  afford  agreeable  recreation,  as  well  as  useful  exer- 
cise.    The   Indian  club,  the  wand,  the   ring,  and  the   light 
wooden  dumb-bell  are  among  the  articles  devised  to  assist  in 
the  smooth  performance  of  class  drill.     Pleasant  music  timed 
to  the  movements  of  the  drill  is  a  further  aid,  just  as  martial 
music  by  a  good  band  is  a  great  help  to  soldiers  on  the  march. 

30.  Home  Gymnastics*  —  This  is  perhaps  a  better  name  than 
parlor  gymnastics  for  those  exercises  which  may  be  practised 
by  individuals  at  home.     Apparatus  of  various   forms,   and 
generally  simple  in  construction,  has  been  devised,  and  may  be 
had  at  small  cost.     It  can  be  set  up  in  almost  any  room  in  the 
house.     In  some  of  these  appliances  cords  or  bands  of  rubber 
and  pulleys  are  used;  in  others,  simply  weights  with  cords 

now,  and  seemingly  care  not  for  the  power  to  work  long,  to  work  well, 
to  work  successfully  hereafter,  which  is  health."  — Dr.  Nathan  Allen  on 
Physical  Culture.  • 

6.  On  Recreation.  —  "  Our  whole  method  of  amusements,  especially  for 
the  young,  should  be  reformed.  Gas-light  should  yield  to  daylight,  night 
vapors  in  heated  and  close  rooms  should  give  way  to  fresh  air  under  the 
open  heavens,  and  our  young  people  should  be  brought  up  to  work  and 
play  under  the  ministry  of  that  great  solar  force  which  is  the  most  benign 
and  god-like  agent  known  to  men.  Ardent  spirits  and  tobacco  should  be 
given  up,  and  in  their  stead  genial  exercise  of  riding,  gymnastics,  and 
the  dance,  with  music  and  all  beautiful  arts,  should  be  employed  to  stir 
the  languid  powers  and  soothe  the  troubled  affections.  The  old  Greeks 
taught  music  and  gymnastics  as  parts  of  education,  and  Plato,  in  urging 
the  importance  of  these,  still  maintains  that  the  soul  is  superior  to  the 
body,  and  religion  is  the  crown  of  all  true  culture.  Why  may  not  Chris- 
tian people  take  as  broad  a  position  on  higher  ground,  and  with  a  generous 
and  genial  culture  associate  a  faith  that  is  no  dreamy  sentiment  or  ideal 
abstraction,  but  the  best  power  of  man  and  the  supreme  grace  of  God." 
—  Bev.  Dr.  Osgood  on  "  The  Skeleton  in  Modern  Society." 


29.  Proper  exercise  at  home  ?    How  obtained  at  home  ?    What  as  to  regularity  ? 

30.  What  kind  of  apparatus  is  recommended  for  home  gymnastics  ?    Why  ?    Describe 
advantages  of  the  "  chest  weight." 


48 


THE  MUSVLES 


and  pulleys,   without  elastic   material.      The   latter  kind  is 
better,  inasmuch  as  the  movement  is  even  and  the  action  of 

the  muscle  steady,  while  with 
rubber  bands  the  farther  they  are- 
stretched  the  greater  is  the  exer- 
tion. No  apparatus  yet  invented 
answers  its  purpose  so  well  as  the 
"  chest  weight "  (see  Fig.  17).  By 
its  use  all  the  prominent  muscles 
of  the  body  are  easily  exercised. 
No  instruction  is  necessary  and 
the  space  occupied  is  easily 
spared.  A  person  is  obliged  only 
to  grasp  the  handles  and  then 
follow  the  simple  directions  given 
to  bring  into  action  whatever 
muscles  or  groups  of  muscles  he 
wishes  to  exercise.  Th'e  weight 
can  be  changed  to  suit  the 
strength  of  the  one  exercising. 
Illustrations  showing  a  few  of 
the  positions  and  movements  that  are  recommended  with  one 
of  the  chest  weights,  are  given  in  the  Appendix,  page  367. 

31.  In  addition  to  the  movements  mentioned  many  others 
might  be  employed,  varying  with  the  particular  muscles  or 
parts  that  require  to  be  exercised.  Combinations  of  cords  and 
pulleys  suitable  for  particular  cases  can  be  made,  and  the 
resistance  of  the  weights  adjusted  to  the  needs  of  the  weakly 
and  the  young,  as  well  as  to  the  most  robust.  These  exercises 
are  by  no  means  limited  to  those  who  are  in  health  and  who 
resort  to  them  as  a  relaxation  from  long  study  or  sedentary 
occupations.  Persons  who  are  not  strong,  who  cannot  take 
advantage  of  school  drill,  or  who  are  convalescing  from  sick- 
ness, may,  under  suitable  conditions,  be  especially  benefited  by 
them.  Not  all  the  movements  should  be  tried  at  first,  but,  on 
the  contrary,  there  should  be  a  careful  selection  of  two  or 
three  that  seem  to  be  best  suited  to  the  needs  of  the  patient. 

81.  Describe  some  exercises  with  the  "chest  weight." 


FIG.  17. — THE  "CHEST  WEIGHT' 


THE   MUSCLES  49 

These  exercises  must  also  be  undertaken  gradually  and  in- 
creased in  proportion  to  the  ability  of  each  individual.  There 
should  be  some  degree  of  uniformity  as  to  the  time  of  day 
as  well  as  to  the  form  and  duration  of  the  gymnastic  effort 
engaged  in.  Remember  always  to  stop  short  of  the  point 
where  manifest  fatigue  begins  to  be  felt,  regardless  of  the 
shortness  or  the  length  of  the  time.  The  keynote  to  beneficial 
home  exercise  is  to  put  into  use  as  many  muscles  as  is  proper 
and  safe,  without  bringing  about  a  feeling  of  exhaustion.  If 
exhaustion  is  produced,  the  exercise  passes  into  violence,  and 
as  we  have  formerly  learned,  violence  is  harmful.  It  must  be 
remembered  that  these  movements  not  only  develop  the  parts 
named,  but  each  movement  exercises  many  other  muscles  at 
the  same  time.  In  Figs.  9  and  10  (App.)  always  take  a  deep 
breath  before  each  motion.  Then  the  pressure  of  the  filled 
lungs,  together  with  the  action  of  the  muscles,  will  more 
quickly  widen  and  deepen  the  thorax. 

32.  Rest.  —  We  cannot  always  be  active :  after  labor  we 
must  rest.     We  obtain  this  rest  partly  by  suspending  all  exer- 
tion, as  in  sleep,  and  partly  by  a  change  of  employment.     It 
is  said  that  Alfred  the  Great  recommended  that  each  day 
should  be  divided  in  the  following  manner  :  "  Eight  hours  for 
work,  eight  hours  for  recreation,  and  eight  hours  for  sleep." 
This  division  of  time  is  as  good  as  any  that  could  now  be 
made,  if  it  be  borne  in  mind  that,  when  the  work  is  physical, 
the  time  of  recreation  should  be  devoted  to  the  improvement 
of  the  mind ;  and  when  mental,  we  should  then  recreate  by 
means  of  physical  exercise. 

33.  *  During  sleep,  all  voluntary  activity  ceases,  the  rapidity 
of  the  circulation  and  breathing  diminishes,  and  the  tempera- 
ture of  the  body  falls  one  or  two  degrees.     In  consequence,  the 
body  needs  warmer  coverings  than  during  the  hours  of  wake- 
fulness.     During  sleep,  the  body  seems  wholly  at  rest,  and  the 
mind  is  also  inactive,  if  we  except  those  involuntary  mental 

82.  Need  of  repose  ?  How  do  we  obtain  rest  ?  Alfred  the  Great  ?  The  eight  hour 
division  of  time  ? 

33.  Cessation  of  voluntary  activity  ?  Temperature  of  the  body  ?  Consequence?  Body 
and  mind  during  sleep  ?  Nutrition  ?  Describe  it.  Consequence  of  insufficient  sleep  ? 


50  THE  MUSCLES 

wanderings  which  we  call  dreams.  Nevertheless  a  very  active 
and  important  physical  process  is  going  on.  Nutrition,  or  the 
nourishing  of  the  tissues,  now  takes  place.  While  the  body  is 
in  action,  the  process  of  pulling  down  predominates,  but  in 
sleep,  that  of  building  up  takes  place  more  actively.  In  this 
way  we  are  refreshed  each  night,  and  prepared  for  the  work 
and  pleasures  of  another  day.  If  sleep  is  insufficient,  the 
effects  are  seen  in  the  lassitude  and  weakness  which  follow. 
Wakefulness  is  very  frequently  the  forerunner  of  insanity, 
especially  among  those  who  perform  excessive  mental  labor. 

34.  All  persons  do  not  require  the  same  amount  of  sleep,  but 
the  average  of  men  need  from  seven  to  nine  hours.     There  are 
well-authenticated  cases  where  individuals  have  remained  with- 
out sleep  for  many  days  without  apparent  injury.     Frederick 
the  Great  required  only  five  hours  of  sleep  daily,  and  Bonaparte 
could  pass  days  with  only  a  few  hours  of  rest.     But  this  long- 
continued  absence  of  sleep  is  attended  with   danger.     After 
loss  of  sleep  for  a  long  period,  in  some  instances,  stupor  has 
come  on  so  profoundly,  that  there  has  been  no  awaking. 

35.  There  are  instances  related  of  sailors  falling  asleep  on 
the  gun-deck  of  their  ships  while  in  action.     On  the  retreat 
from  Moscow,  the  French  soldiers  would  fall  asleep  on  the 
march,  and  could  only  be  aroused  by  the  cry,  "  The  Cossacks 
are  coming ! "    Tortured  persons  are  said  to  have  slept  upon 
the  rack  in  the  intervals  of  their  torture.     In  early  life,  while 
engaged  in  a  laborious  country  practice,  the  writer  not  unfre- 
quently  slept  soundly  on  horseback.     These   instances,   and 
others,  show  the  imperative  demand  which  nature  maizes  for 
rest  in  sleep. 

36.  Alcohol  and  Strength.  —  Alcohol,  a  substance  to  be  fully 
described  in  our  subsequent  chapter  on  Food  and  Drink,  merits 
consideration  at  this  point  by  reason  of  the  mistaken  views 
held  by  many  as  to  its  beneficial  effects  upon  the  muscles, 

34.  Amount  of  sleep  for  different  persons  ?    Cases  f    Frederick  the  Great  ?    Bonaparte  ? 
Instances  of  long  deprivation  of  sleep  ? 

35.  Instances  of  sailors  ?    French  soldiers  ?    During  torture  ? 
86.  The  former  use  of  grog. 


THE  MUSCLES  51 

when  they  are  put  into  vigorous  use,  and  especially  into  daily 
manual  labor.  It  is  well  known  that  for  generations  it  was 
thought  to  be  essential  to  every  army  and  navy  of  the  civilized 
world  that  "grog"  —  which  contains  alcohol — should  be  regu- 
larly issued  to  the  hard-worked  soldier  and  sailor,  especially 
when  they  were  in  the  actual  service  of  war.  To  the  slaves, 
also,  on  many  plantations,  during  the  days  of  slavery  in  this 
country,  a  daily  ration  of  rum  was  given  out  in  the  busy 
seasons,  in  the  belief  that  thus  better  results,  in  regard  to  the 
amount  of  muscular  labor,  were  secured.  So,  too,  in  nearly 
every  walk  of  life  where  hard  muscular  labor  was  demanded, 
a  similar  belief  and  practice  commonly  prevailed,  and  some 
form  of  alcohol  was  resorted  to  as  a  trusty  servant  whenever 
any  great  or  unusual  amount  of  labor  was  to  be^  called  forth. 

37.  How  Alcohol  affects  the  Muscles. — The  scientific  progress 
of  recent  years,  however,  has  put  the  question  in  a  different 
light,  and  it  is  now  the  commonly  received  view  of  scientific 
men  that  the  benefits  to  labor  derived  from  alcohol  were  ap- 
parent and  not  real.     Alcohol  adds  nothing  to  our  bodily 
energy ;  it  may  spur  up  the  muscles  to  a  temporary  and  extra- 
ordinary exertion,  but  it  does  not  strengthen  the  muscles  any 
more  than  does  the  whip  or  the  spur,  that  is  applied  to  a  hard- 
laboring  horse  to  make  him  go  faster,  add  to  his  strength. 

38.  Experiments  have  been  made  with  instruments  con- 
structed for  the  purpose,  and  the  results  carefully  recorded, 
and  these  show  that  a  less  degree  of  muscular  power  is  pos- 
sessed by  the  same  person  when  he  is  under  the  influence  of 
alcohol  than  when  he  has  not  taken  it  (see  foot-note  on  p.  241). 
This  is  no  secret  to  men  who  go  into  training  to  bring  about 
the  best  possible  development  of  their  muscular  strength ;  men 
who  intend  to  engage  in  contests,  such  as  boat-racing,  foot- 
racing, and  a  great  variety  of  other  athletic  sports,  are  taught 
to  abstain  entirely  from  all  forms  of  drink  that  contain  alcohol 
if  they  would  bring  their  powers  to  the  highest  point.     The 
endurance  of  severe  and  prolonged  bodily  labor  is  not  favored 

37.  Present  belief  as  to  its  use  ? 

88.  What  experiments  have  been  tried  ?    Training  of  athletes  ?    What  experience  of 
soldiers  ? 


52  THE  MUSCLES 

by  the  use  of  alcohol.  The  test  recently  made  upon  the  British 
troops  during  the  war  in  the  Soudan,  showed  that  the  exhaust- 
ing work,  privation,  and  the  burning  heat  of  the  desert  can  be 
better  endured  by  those  who  have  not,  than  by  those  who  have 
the  ration  of  grog.  The  time  is  coming  when  this  ration  will 
be  a  thing  of  the  past,  and  that,  too,  for  good  scientific  reasons. 

39.  Abnormal  Movements  due  to  Alcohol. — The  amount  of 
disturbance  in  the  muscular  system  that  is  produced  by  alcohol 
varies  greatly  under  different  circumstances.  It  may  be  very 
great  or  very  slight  according  as  a  great  or  small  dose  of  liquor 
is  taken.  The  tongue,  the  organ  of  speech,  is  a  muscle  that 
early  betrays  the  presence  of  drink.  This  is  the  cause  of  what 
is  called  the  "  thick  "  speech  of  the  drunken  man,  whose  words 
are  not  correctly  uttered  but  are  dropped,  cut  short  or  run 
together-  in  an  unusual  and  oftentimes  unintelligible  manner. 
"  Seeing  double  "  is  another  muscular  disturbance  observed  in 
drunkenness.  At  a  certain  stage  of  the  drunken  fit  every 
single  object  appears  to  the  victim  to  be  double.  In  this  case 
the  muscles  that  move  the  eyeballs  are  at  fault;  they  are 
temporarily  deranged,  so  that  the  two  eyeballs  cease  to  move 
harmoniously  and  are  no  longer  brought  to  bear  upon  the 
objects  before  them,  as  in  health,  and  the  images  of  two  objects 
are  reported  to  the  brain,  while  in  reality  there  is  only  one. 
Then,  too,  objects  that  are  at  rest  appear  to  be  in  motion, 
because  the  eyeballs  are  affected  by  an  unsteady,  rolling 
motion.  This  is  one  reason  why,  at  a  certain  stage,  the 
drunken  man  who  tries  to  walk  abroad,  begins  to  stagger  from 
side  to  side  over  the  sidewalk,  to  stumble  and  perhaps  to  fall, 
and  sober  men  appear  to  him  to  stagger  and  be  drunk.  The 
muscles  of  his  limbs  also,  in  their  turn,  becoming  weakened, 
or  not  being  properly  controlled,  may  refuse  to  sustain  the  for- 
lorn pedestrian,  and  he  may  be  seen  clinging  for  support  to 
some  friendly  lamp-post,  or,  later  on,  sinking  powerless  into 
the  gutter. 

39.  Does  alcohol  derange  the  muscles  ?  What  effect  upon  the  tongue  ?  The  eyes  and 
limbs? 


THE  Mi'SCLES 


53 


f  VOLUNTARY 

^FTFTAL        MUSCLK 
SKELETAL.      (Striated  or 

I  Striped.) 


TOPICAL    OUTLINE 

Under  the  control  of  the  will. 

Composed  of  bundles  of  fibres. 

These  bundles  composed  of  smaller 
bundles  (fasciculi),  visible  to  the 
unaided  eye,  and  surrounded  by 
sheaths. 

Fasciculi  composed  of  fibres.  Average 
diameter  about  B5o  in. 

Fibres  made  up  of  minute  fibrillx 
(fibrils). 

Fibrillae  composed  of  disk-like-  bodies, 
and  consequently  striated  trans- 
versely. 

Grouped  bi-laterally  and  in  pairs. 

Attached  to  bones  by  tendons  or  di- 
rectly. 

I  Not  under  the  control  of  the  will. 
Found  chiefly  in  the  muscular  walls 
juuov^c..  of  the  internal  organs  and  vessels. 

(Non-striated  or  1  Fibres   composed   of   elongated   cells 
Unstriped.)  with  pointed  ends,  not  marked  trans- 

L      versely. 

Involuntary,  yet  striped  or  striated. 
Striated    longitudinally   as   well    as 

transversely. 
Fibres     composed     of    oblong     and 

branched  cells. 

III.  USES  —  motion ;  shape ;  protection  ;  hold  bones  in  place. 

IV.  HYGIENE  —  nourishment  from  blood;  exercise:  rest;  effects  of  alcohol 

on  strength ;  endurance,  structure. 


VISCERAL. 


MUSCLES  OF 
THE  HEART. 


TABLE   OF   THE   PRINCIPAL    MUSCLES 
(SEE  FIGURE  11,  PAGE  32) 


The  Head 

Oc-cip'i-to— fron-ta'lis,  moves  the  scalp  and  eyebrows. 

Or-bic-u-la'ris  pal'pe-brae,  closes  the  eye. 

Le-va'tor  pal'pe-brae,  opens  the  eye. 

The  Recti  muscles  (four  in  number)  move  the  eyeball. 

Tem'po-ral, 

Mas-se'ter, 


raise  the  lower  jaw. 


The  Neck 

Pla-tvs'ma  My-oi'des,  {  moye  ^  head  forwards. 

Ster'no  Mas  toid, 

Sca-le'ni  muscles  move  the  neck  from  side  to  side. 


54  THE  MUSCLES 


The  Trunk 

Pec-to-ra'lis,  moves  the  arm  forwards. 

La-tis'si-mus  dor'si,  moves  the  arm  backwards. 

Tra-pe'zi-us,  1 

Ser-ra'tus  mag'nus,  \  move  shoulder-blade. 

Rhom-boi-de'us,         J 

In-ter-cos'tals,  move  the  ribs  in  respiration. 


E-rect'or  spi'nae,  move  the  trunk  backwards. 

The  Upper  Limb 

Del'toid,  raises  the  arm. 

Te'res  ma'jor,  lowers  the  arm. 

Sub-scap-u-la'ris, 

Spi-na'tus, 

Bi'ceps,  bends  forearm. 

Tri'ceps,  straightens  forearm. 

Pro-na'tor,     j  rotate  forearm. 

Su-pi-na  tor, ) 

Flex'or  car'pi  ra-di-a'lis,      "] 

Fiex'or  car'pi  ul-na'ris,      '      move  the  han(L 

Ex-ten'sor  car'pi  ra-di-a'lis, 

Ex-ten'sor  car'pi  ul-na'ris,   J 

More  than  thirty  muscles  take  part  in  moving  the  fingers 

The  Lower  Limb 
Il-i'a-cus, 
Pso'as  mag'nu 
Pec-tin-e'us, 
Ad-duc'tor, 

Glu-te'us,        j  moye  the  thi  h  backwards. 
Pyr-i-form  is,  ) 

Sar-to'ri-us  (from  Sar'tor,  a  tailor),  crosses  one  thigh  over  the  other. 
Rec'tus,  /  move  tne  j     forwards. 
Vas'tus,  ) 

Bi'ceps,     I  move  tlie  ieg  backwards. 
Grac'i-lis,  ) 
Tib-i-a'lis,  ] 


So-le'us, 

Twenty  muscles  take  part  in  moving  the  toes. 


QUESTIONS    FOR   TOPICAL    REVIEW 

PAGB 

1.  What  can  you  state  of  the  number  and  division  of  the  muscles  ? 33 

2.  Describe  the  structure  of  the  muscles 33,  34 

3.  Their  arrangement  in  pairs  and  consequent  action 35 


THE  MUSCLES  55 


4.  What  is  the  difference  between  the  motion  called  flexion  and  that 

called  extension  ?  35 

5.  Describe  their  action,  and  state  which  are  the  more  powerful 36 

6.  What  is  the  difference  between  voluntary  and  involuntary  muscles?        36 

7.  Illustrate  the  difference  between  the  two 36 

8.  State  all  you  can  of  the  tendons  or  sinews 36,  37 

9.  What  is  meant  by  contraction  of  the  muscles  ? 37 

10.  In  how  many  and  what  ways  may  contraction  be  effected 38 

11.  What  is  stated  of  after-death  contraction  ? 38 

12.  Why  cannot  a  muscle  in  life  continue  contracted  a  long  time? 38 

13.  How  then  can  the  constant  beating  of  the  heart  be  explained  ? 39 

14.  How  does  the  strength  of  a  man  compare  with  that  of  a  horse? 40 

15.  What  can  you  state  in  regard  to  the  relative  strength  of  animals  ? . .        40 

16.  What,  in  relation  to  physical  strength  ? 40 

17.  What,  in  relation  to  physical  degeneracy  ? 40,  41 

18.  What,  in  relation  to  the  importance  of  exercise  ? 41 

19.  What  is  the  effect  of  exercise  upon  the  heart,  skin,  and  appetite  ?  . .  41,  42 

20.  How  does  exercise  affect  the  current  of  the  body's  circulation  ?  . . . .        42 

21.  How  does  judicious  exercise  affect  the  muscles  ? 42 

22.  What  is  stated  of  violent  and  spasmodic  exercise  ? 42 

23.  Of  the  exercise  of  walking  ? 43 

24.  Of  running,  leaping,  and  other  modes  of  exercise  ? 43,  44 

25.  Of  physical  culture,  in  connection  with  out-door  exercises  ? 44 

26.  What  are  the  results  of  excessive  exercise  ? 45 

27.  Of  the  importance  of  gymnastics  in  our  schools  and  colleges  ? 45,  46 

28.  Of  the  importance  of  rest  from  labor  or  exercise  ? 49 

29.  What  processes  take  place  during  sleep  ? 49 

30.  What  about  the  amount  of  sleep  required  ? 50 

31.  What  effects  follow  insufficient  sleep  ? 50 

32.  Illustrate  nature's  demand  for  sleep 50 


CHAPTER  III 

THE  INTEGUMENT,  OR  SKIN 

The  Integument— Its  Structure  —  The  Nails  and  Hair—  The  Complex- 
ion—  The  Sebaceous  Glands —  The  Perspiratory  Glands — Perspiration 
and  Its  Uses  —  Importance  of  Bathing  —  Different  Kinds  of  Baths  — 
'Manner  of  Bathing —  The  Benefits  of  the  Sun  —  Importance  of  Warm 
Clothing  —  Poisonous  Cosmetics 

1.  The  Skin. — The  skin  is  the  outer  covering  of  the  body. 
The  parts  directly  beneath  it  are  very  sensitive,  and  without 
its  protection  life  would  be  an  agony,  as  is  shown  whenever  by 
accident  the  skin  is  broken  or  torn  off,  the  bared  surface  being 
very  tender,  and  sensitive  even  to  exposure  to  the  air.    Nature 
has  provided  the  body  with  a  garment  that  is  soft,  pliable, 
close-fitting,  and  very  thin ;  and  yet  sufficiently  strong  to  ena- 
ble us  to  come  in  contact  with  the  objects  that  surround  us, 
without  inconvenience  or  suffering. 

2.  The  Structure  of  the  Skin. — When  examined  under  the 
microscope,  the  skin  is  found  to  be  made  up  of  two  layers  — 
the  outer  and  the  inner.     The  inner  one  is  called  the  cutis,  or 
true  skin ;  the  outer  one  is  the  epidermis,  or  scarf-skin.     The 
latter  is  also  known  as  the  cuticle.    These  two  layers  are  closely 
united,  but  they  may  be  separated  from  each  other.    This  sepa- 
ration takes  place   whenever,  from  a  burn  or  other  cause,  a 
blister  is  formed ;  a  watery  fluid  is  poured  out  between  the 
two  layers,  and  lifts  the  epidermis  from  the  true  skin.     Of  the 
two  layers,  the  cuticle  is  the  thinner  in  most  parts  of  the  body, 
and  has  the  appearance  of  a  whitish  membrane.     It  is  tough 

1.  What  is  the  skin  ?    Parts  directly  beneath  ?    What  is  shown  ? 

2.  Microscopic  examination  ?    What  is  the  cutis?     The  cuticle  ?    Their  union  ?    How 
separated  ?    What  further  is  said  of  the  cuticle  ? 


THE  INTEGUMENT,    OR  tfA'AV  57 

and  elastic,  is  without  feeling,  and  does  not  bleed  when  cut. 
Examine  it  more  closely,  and  we  observe  that  it  is  composed 
of  minute  flat  cells,  closely  compacted,  and  arranged  layer 
upon  layer. 

3.  The  outer  layer,  the  epidermis,  is  constantly  being  worn 
out,  and  falls  from  the  body  in  the  form  of  very  fine  scales. 
The  scales  are  dead  cells,  which  are  loosened,  either  singly  or 
in  groups.     Sometimes  large  portions  of  the  epidermis  are  thus 
removed.    In  the  scalp  such  portions  are  called  dandruff.    The 
parts  which  roll  up  on  the  skin  when  it  is  thoroughly  moist- 
ened by  perspiration  or  the  bath  are  from  the  epidermis.    The 
"  peeling  "  of  scarlet  fever  comes  from  the  same  source.     But 
the  epidermis  does  not  wear  out.      It  is  constantly  renewed 
from  the  surface  of  the  cutis.     Here  new,  delicate,  round  cells 
are  constantly  being  formed,  each  new  layer  crowding  its  pred- 
ecessors nearer  the  surface.     Where  the  surface  of  the  body 
is  most  subject  to  friction,  as  in  the  palm  of  the  hand  and 
soles  of  the  feet,  new  cells  form  most  rapidly,  and  consequently 
the  epidermis  becomes  exceptionally  hard  and  thick. 

4.  The  cutis,  or  true  skin,  lies  beneath  the  epidermis,  and  is 
its  origin  and  support.     It  is  firm,  elastic,  very  sensitive,  and 
is  freely  supplied  with  blood-vessels.     Hence,  a  needle  entering 
it  not  only  produces  pain,  but  draws  blood.      It  is   closely 
connected  with  the  tissues  below  it,  but  may  be  separated  by 
means  of  a  sharp  instrument.     The  surface  of  the  cutis  is  not 

1.  The  Renewal  of  the  Cuticle.  —  The  skin  is  not  a  permanent  sheath, 
but  is,  as  it  were,  always  wearing  out  and  rubbing  off,  and  new  skin  is 
always  rising  up  from  underneath.  A  snake  leaves  off  his  whole  skin  at 
once,  as  we  leave  off  a  suit  of  clothes  or  a  dress,  and  sometimes  we  may 
find  his  whole  cast-off  covering  turned  inside  out,  just  as  he  crept  out  of 
it.  In  man,  generally,  we  do  not  notice  the  dead  particles  of  the  skin  as 
it  wears  off ;  but  where  the  cuticle  is  pretty  thick,  as  on  the  soles  of  the 
feet,  we  can  see  it  peel  off  in  little  rolls  whenever  we  wash  the  feet  in  hot 
water.  After  scarlet  fever,  too,  sometimes  the  dead  skin  comes  off  in 
great  flakes,  and  from  the  hands  almost  like  the  fingers  of  a  glove. 
—  Berners. 

3.  Wearing  out  of  the  cuticle  ?    What  then  ?    Variety  In  thickness  of  cuticle  ?    How 
accounted  for? 

4.  Location  and  office  of  the  cutis  ?    What  further  is  said  of  it  ?    Papillae?    Touch? 


58 


THE  INTEGUMENT,   OR  SKIN 


smooth,  but  covered  here  and  there  with  minute  elevations', 
called  papillce.  These  are  arranged  in  rows,  or  ridges,  such  as 
those  which  mark  the  palm  and  thumb ;  their  number  is  about 
80  to  the  square  line  (a  line  being  one-twelfth  of  an  inch). 
These  papillce  contain  blood-vessels  and  nerves  also,  and  are 
largely  concerned  in  the  sense  of  touch;  hence  they  are 
abundant  where  the  touch  is  most  delicate,  as  at  the  ends 
of  the  fingers.  The  skin  is  fastened  to  the  underlying  tissues 
by  a  loose  elastic  (areolar)  tissue.  This  contains  fat  during 
youth  and  middle  life.  The  gradual  absorption  of  this  fat  as 

old  age  approaches  gives  the 
skin  a  wrinkled  appearance. 
This  layer  is  called  the  sub- 
cutaneous layer. 

5.    The    Nails    and    Hair. — 

These  are  modified  forms  of 
the  cuticle.  The  nail  grows 
from  a  fold  of  the  cuticle  at 
the  root,  and  from  the  under 
surface.  As  fast  as  it  is 
formed,  it  is  constantly  being 
pushed  outward.*  The  rapidity 
of  its  growth  can  be  ascertained 
by  filing  a  slight  groove  on  its 

THK  ROOT  OF  A  HAIR  HIGHLY  MAGNIFIED  gurface?    an(J    noticing    how    the 


FIG.  18 


rr.7>. 


of  the  nail  increases,  in  the 
course  of  a  few  weeks.  When  the  nail  is  removed  by  an 
accident,  it  will  be  replaced  by  a  new  one,  if  the  root  be 
not  injured.  (Notes  2  and  6.) 

*The  practice  of  biting  the  nails  should  be  avoided  not  only  because 
of  the  ugly  shape  which  is  produced,  but  because  it  impairs  the  sense  of 
touch  in  the  ends  of  the  fingers.  In  paring  the  nails,  let  them  remain  long 
enough  nearly  to  cover  the  pulp  of  the  finger.  Avoid  scraping  either  sur- 
face of  the  nail  ;  do  not  injure  the  "  quick." 

2.   The  Life  of  the  Cells  of  the  Body.  —  "  The  life  of  the  body  is  long 


5.   What  are  the  nails  and  hair  ?    The  growth  of  the  nail  ?    The  rapidity  of  its  growth  ? 
Accident  to  the  nail  ? 


THE  INTEGUMENT,   OR  SKIN  59 

6.  The  hairs  are  produced  in  a  similar  manner;  the  skin 
forming  depressions,  or  hair-sacs,  from  the  bottom  of  which 
they  grow  and  are  nourished  (Fig.  18).     They  are  found,  of 
greater  or  less  length,  on  almost  all  parts  of  the  surface,  except 
the  palms  of  the  hands  and  soles  of  the  feet.     On  certain  parts 
of  the  body,  they  grow  to  great  length ;  on  other  parts  they 
are  so  short,  that  they  do  not  rise  beyond  the  hair-sac  from 
which  they  grow. 

7.  The  bulb,  or  root,  from  which  the  hair  arises,  is  lodged 
in  a  small  pouch,  or  depression  of  the  skin.     The  shaft  is  the 
part  which  grows  out  beyond  the  level  of  the  skin.     Its  growth 
is  altogether  in  one  direction,  in  length  alone.     The  outer  part 
of  the  hair  is  quite  firm,  while  its  interior  is  softer,  and  supplies 
the  nutriment  by  which  it  grows.     The  hair  is  more  glossy  in 
health  than  at  other  times. 

8.  The  nail  serves  as  a  protection  to  the  end  of  the  finger, 
and  also  enables  us  to  grasp  more  firmly,  and  to  pick  up  small 
objects.     The  hair,  too,  is  a  protection  to  the  parts  it  covers. 
On  the  head,  it  shields  the  brain  from  extremes  of  heat  and 
cold,  and  moderates  the  force  of  blows  upon  the  scalp.     On 
the  body,  it  is  useful  in  affording  a  more  extensive  surface  for 
carrying  off  the  perspiration. 

under  fortunate  circumstances  ;  that  of  our  cells  is  short.  We  all  know 
that  the  surface  of  the  body  is  covered  by  layers  of  cells.  The  super- 
ficial layers  are  in  loose  connection  ;  they  are  cells  hi  old  age.  The  fric- 
tion of  our  clothing  daily  removes  an  immense  number  of  them.  A 
cleanly  person  who  uses  sponge  and  towel  energetically  every  day  rubs  off 
a  still  greater  quantity. 

"  We  swallow  ;  our  tongue  acts  in  speaking  ;  drink  and  food  pass  this 
way.  Now,  the  mucous  membrane  of  the  mouth  is  covered  with  layers 
of  cells.  Here,  also,  many  thousand  senile  cells  are  rubbed  off  daily. 
And  so  on  through  the  entire  digestive  tract.  An  immense  number  of 
cells—  these  living  corner-stones  of  the  body — is  thus  lost  daily. 

"  To  show  the  duration  of  life  in  one  kind  of  cell,  let  us  turn  to  the 
human  nail.  The  latter,  growing  from  a  furrow  of  the  skin,  is  made  up 
of  skin-cells.  In  the  depth  of  the  furrow,  youth  prevails ;  at  the  upper 
margin — which  we  trim  —  old  age.  Berthold  proved  that  a  nail-cell 


6.  How  are  the  hairs  produced  ?    Difference  in  their  length  ? 

7.  Boot  of  the  hair  ?    Shaft  ?    Firmness  and  softness  of  the  hair  ? 

8.  Office  of  the  nail  ?    Of  the  hair  ?    Give  the  illustrations. 


60 


THE  INTEGUMENT,    OR  SKIN 


9.  Complexion.  —  In.  the  deeper  cells  of  the  cuticle  lies  a 
pigment,  or  coloring-matter,  consisting  of  minute  colored  grains. 
On  this  pigment  complexion  depends ;  and  its  presence,  in  less 
or  greater  amount,  occasions  the  difference  of  hue  that  exists 
between  the  light  and  the  dark  races  of  men,  and  between  the 
blonde  and  the  brunette  of  the  white  races.     Freckles  are  due 
to  an  irregular  increase  of  this  coloring  matter. 

10.  The  sun  has  a  powerful  influence  over  the  development 
of  this  pigment,  as  is  shown  by  the  swarthy  hue  of  those  of 
the  white  race  who  have  colonized  in  tropical  climates.     It  is 

also  well  illustrated  by  the  fact, 
that  among  the  Jews  who  have 
settled  in  northern  Europe, 
there  are  many  who  are  fair- 
complexioned,  while  those  re- 
siding in  India  are  as  dark  as 
the  Hindoos  around  them. 


11.  An  Albino  is  a  person 
who  may  be  said  to  have  no 
complexion ;  that  is,  there  is 
an  entire  absence  of  coloring 
matter  from  the  skin,  hair,  and 
iris  of  the  eye.  This  condition 
exists  from-  birth,  and  more 
FIG.  19.— SHOWING  A  HAIR  AND  SECTION  frequently  occurs  among  the 

OF  SKIN  HIGHLY  MAGNIFIED  dafk  raceg?  and  jn  h()t  climates, 

although  it  has  been  observed  in  almost  every  race  and  clime. 

12.   Sebaceous  Glands. — In  all  parts  of  the  surface  where 
the  hairs  grow,  are  to  be  found  the  sebaceous,  or  oil-producing 

lives  four  months  in  summer  and  five  in  winter.  A  person  dying  in  his 
80th  year,  has  changed  his  nail  200  times,  at  least  —  and  the  nail  appeared 
such  an  inanimate,  unvarying  thing  !  No  other  cells,  we  believe,  have  a 
life  nearly  so  long  as  that  of  the  nail." —  Compendium  of  Histology  by 
Heinrich  Frey. 

9.   On  what  does  the  complexion  depend  ?    Light  and  dark  races  ?    Freckles  ? 

10.  Influence  of  the  sun  ?    How  illustrated  ?    Jews  ? 

11.  What  is  an  Albino  ?    Where  are  Albinos  found  ? 

12.  What  are  sebaceous  glands  ?    How  do  they  act  ?    Sebaceous  glands  of  the  face  ? 
How  do  they  act  ? 


THE  INTEGUMENT,    OR  SKIN  61 

glands.  These  glands  are  little  rounded  sacs,  usually  connected 
with  the  hair-bulbs;  and  upon  these  bulbs  they  empty  their 
product  of  oil,  which  acts  as  a  natural  dressing  for  the  hair 
(Fig.  18).  A  portion  of  the  sebaceous  matter  passes  out  upon 
the  surface,  and  prevents  the  cuticle  from  becoming  dry  and 
hard.  The  glands  situated  upon  the  face  and  forehead  open 
directly  upon  the  skin.  In  these,  the  sebaceous  matter  is 
liable  to  collect,  and  become  too  hard  to  flow  off  naturally. 

13.  These  glands  on  the  face  and  forehead  frequently  appear 
on  the  faces  of  the  young  as  small,  black  points,  which  are 
incorrectly  called  "  worms."     Jt  is  true,  that 

occasionally  living  animalcules  are  found  in 
this  thickened  sebaceous  matter,  but  they  can 
only  be  detected  by  the  aid  of  the  micro- 
scope. This  sebaceous  matter  acts  not  only 
to  keep  the  skin  flexible,  and  furnish  for 
the  hair  an  oily  dressing,  but  it  especially 
serves  to  protect  the  skin  and  hair  from  the 
acridity  arising  from  the  perspiration, 

14.  The  Perspiratory  Glands.  —  The  chief 
product  of  the  skin's  action  is  the  perspira- 
tion.    For  the  formation  of  this,  there  are 
furnished  countless  numbers  of  little  sweat- 
glands  in  the  true  skin.     They  consist  of  fine 
tubes,  with  globe-like  coils  at  their  deeper 
extremity.     Their  mouths  or  openings  may 

J    .  J   FIG.      20.  —  MAGNIFIED 

be  seen  with  an  ordinary  magnifymg-glass,  VIEW  OF  A  SWEAT- 
upon  the  fine  ridges  which  mark  the  fingers.  g^D'  WITH  ™ 
These  tubes,  if  uncoiled,  measure  about  one-  «,  the  gland  surrounded 
tenth  of  an  inch  in  length.  In  diameter  ^f^^ 
they  are  about  one  three-hundredth  of  an  dermis ;  c,  its  coatinu- 

,»,  •   ,«       i      i       .1  ation  through  the  rete 

inch,  and  upon  parts  of  the  body  there  are  mucosum,  and  <f, 
not  far  from  three  thousand  of  these  glands  <;brou?h  the  u?Per  *&- 

G.6rmis 

to  the  square  inch.     Their  whole  number  in 

the  body  is,  therefore,  very  great  j  and  it  is  computed,  if  they 

13.  Black  points,  called  worms  ?    Animalcules  ?    Service  performed  by  sebaceous  matter  ? 

14.  Perspiration  ?    Sweat  glands  ?    Of  what  do  they  consist  ?    Dimension  of  the  tubes  f 


62  THE  INTEGUMENT,    OR  SKIN 

were  all  united,  end  to  end,  their  combined  measurement  would 
exceed  three  miles. 

15.  The  Sensible  and  Insensible  Perspiration.  —  The  pores  of 
the  skin  are  constantly  exhaling  a  watery  fluid;   but,  under 
ordinary  circumstances,  there  is  no  moisture  apparent  upon 
the  surface,  for  it  evaporates  as  rapidly  as  it  is  formed.     This 
is  called  insensible  perspiration.     Under  the  influence  of  heat 
or  exercise,  however,  this  fluid  is  formed  more  abundantly, 
and  appears  on  the  surface  in  minute,  colorless  drops.     It  is 
then  termed  'sensible  perspiration. 

16.  Water  is  the  chief  component  of  this  fluid,  there  being 
about  ninety-eight  parts  of  water  to  two  parts  of  solid  matter. 
The  quantity  escaping  from  the  body  varies  greatly,  according 
to  the  temperature  of  the  air,  the  occupation  of  the  individual, 
and  other  circumstances.     The  average  daily  amount  of  per- 
spiration in  the  adult  is  not  far  from  two  pints,  or  more  than 
nine  grains  each  minute. 

17.  The  Uses  of  the  Perspiration. — Besides  liberating  from 
the  blood  this  large  amount  of  water,  with  the  worn-out  matter 
it  contains,  the  perspiration  serves  to  regulate  the  temperature 
of  the  body.     That  is  to  say,  as  evaporation  always  diminishes 
temperature,  so  the  perspiration,  as  it  passes  off  in  the  form 
of  fine  vapor,  cools  the  surface.     Accordingly,  in  hot  weather 
this  function  is  much  more  active,  and  the  cooling  influence 
increases  in  proportion.     When  the  air  is  already  charged  with, 
moisture,  and  does  not  readily  receive  the  vapor  of  the  body, 
the  heat  of  the   atmosphere   apparently  increases,   and  the 
discomfort  therefrom  is  relatively  greater. 

18.  The  importance  of  perspiration  is  shown  by  the  effects 
that  often  follow  its  temporary  interruption,  namely,  headache, 
fever,  and  the  other  symptoms  that  accompany  "taking  cold." 
When  the  perspiration  is  completely  checked,  the  consequences 

15.  What  is  sensible  perspiration  ?    Insensible  perspiration  ? 

16.  Components  of  perspiration  ?    Upon  what  does  perspiration  depend  ?    Amount  of 
perspiration  daily  ? 

17.  What,  does  perspiration  set  free  from  the  blood  ?    What  other  service  does  perspira- 
tion perform  ?    Explain  the  process. 

18.  Effect  of  interruption  of  excretion  ?    What  experiments  are  mentioned  f 


THE  INTEGUMENT,   OR  SKIN  63 

are  very  serious.  Experiments  have  been  performed  upon 
certain  smaller  animals,  as  rabbits,  to  ascertain  the  result  of 
closing  the  pores  of  the  skin.  When  they  are  covered  by  a 
coating  of  varnish  impervious  to  water  and  gases,  death  ensues 
in  from  six  to  twelve  hours  —  the  attendant  symptoms  resem- 
bling those  of  suffocation.  (Head  Note  3.) 

19.  It  is  related  that,  at  the  coronation  of  one  of  the  Popes, 
about  three  hundred  years  ago,  a  little  boy  was  chosen  to  act 
the  part  of  an  angel ;  and,  in  order  that  his  appearance  might 
be  as  gorgeous  as  possible,  he  was  covered  from  head  to  foot 
with  a  coating  of  gold-foil.  He  was  soon  taken  sick,  and 
although  every  known  means  we're  employed  for  his  recovery, 
except  the  removal  of  his  fatal  golden  covering,  he  died  in  a 
few  hours.* 

3.  On  Taking  Cold.  —  "  Of  all  the  things  tp  which  humanity  is  liable, 
there  is  none  which  recurs  more  frequently,  and  whose  consequences  are 
more  troublesome  and  often  dangerous,  than  '  taking  cold.'  Some  persons 
have  quite  a  faculty  for  taking  cold,  while  others  do  so  but  rarely.  And 
yet  the  one  does  not  argue  delicacy  of  constitution,  or  the  other  strength. 
The  body  of  man  has  a  constant  and  agreeable  temperature  in  health,  the 
variation  being  slight.  In  fact,  any  great  variation  is  incompatible  with 
health,  and  constitutes  disease.  Clothes,  by  preventing  the  radiation 
away  of  heat  from  the  surface,  retain  it,  and  so  the  feeling  of  cold  is  not 
so  great  —  that  is,  the  surface  does  not  become  so  cold.  Clothes  are  non- 
conductors, of  heat  when  dry  ;  but  let  them  be  saturated  with  water,  and 
unless  the  loss  of  heat  be  met  by  increased  production,  there  is  a  lowering 
of  the  body  temperature  —  *  taking  cold.'  Thus,  if  exertion  be  continued, 
and  more  heat  is  produced  to  meet  the  loss  until  a  change  of  dry  clothing 
is  procurable,  no  injury  results.  But  let  the  wet  clothes  be  worn  without 
a  corresponding  heat  production,  as  when  children  sit  down  in  school  in 
their  wet  clothes,  or  the  shop-boy  stands  in  his  moist  garments ;  then 
there  is  a  rapid  loss  of  heat,  a  lowering  of  the  body  temperature,  and  a 
cold  is  '  caught.'  So  is  a  cold  caught  by  wet  feet,  when  the  heat  is  radi- 
ated away  from  the  feet ;  if  exercise  be  continued  the  cold  is  not  experi- 
enced. A  damp  bed  gives  cold  because  the  moist  bedclothes  conduct 
away  the  heat,  and  the  body  temperature  is  lowered."  —  Father  gill  on  the 
Maintenance  of  Health. 

*  A  clogged  action  of  the  skin  is  disastrous  in  many  diseases,  -but 
especially  those  attended  by  an  eruption,  or  "breaking  out."  One  of 
these  —  small-pox  —  is  exceeding  fatal  among  the  American  Indians,  whole 
tribes  having  been  swept  away  by  it.  And  this  is  explained  by  the  fact 


19.  Give  the  story  la  relation  to  the  boy  covered  witli  gold-toil. 


64  THE  INTEGUMENT,    OR  SKIN 

20.  The  Importance  of  Bathing.  —  From  these  considerations, 
it  is  evident  that  health  must  greatly  depend  upon  keeping  the 
skin  clean.     "He  who  keeps  the  skin  ruddy  and  soft,  shuts 
many  gates  against  disease."    For  as  the  watery  portion  of  the 
perspiration  evaporates,  the  solid  matter  is  left  behind.     There, 
also,  remain  the  scales  of  the  worn-out  cuticle,  and  the  excess 
of  sebaceous  matter.     In  order  to  secure  the  natural  action  of 
the  skin,  these  impurities  require  to  be  removed  by  the  fre- 
quent application  of  water.     (Bead  Note  4.) 

21.  In  warm  climates,  and  during  hot  weather,  bathing  is 
especially  necessary.'    For  a  person  in  good  health,  a  daily 
cold  bath  is  advisable.     To  this  should  be  added  occasionally 
a  warm  bath,  with  soap,  water  alone  not  being  sufficient  to 
remove  impurities  of  a  greasy  nature.     Soap  facilitates  this, 
by  forming  with  such  substances  a  chemical  mixture,  which  is 
taken  up  by  water,  and  by  it  removed  from  the  body.     (Bead 
Note  5.) 

that  they  habitually  close  their  pores  by  covering  their  bodies  with  bears' 
grease,  as  a  protection  against  the  cold,  and  with  earthy  paints  as  a  means 
of  decoration. 

4.  Bathing.  —  "  When  the  civilization  of  Egypt,  Greece,  and  Rome 
faded,  the  world  passed  through  dark  ages  of  mental  and  physical  bar- 
barism.    For  a  thousand  years  there  was  not  a  man  or  woman  in  Europe 
that  ever  took  a  bath,  if  the  historian  of  those  times,  Michelet,  is  to  be 
believed.     No  wonder  that  there  came  the  wondrous  epidemics  of  the 
middle  ages,  which  cut  off  one-fourth  of  tlie  population  of  Europe  —  the 
spotted  plague,  the  black  death,  sweating  sickness,  and  the  terrible  mental 
epidemics  which  followed  in  their  train — the  dancing  mania,  the  mewing 
mania,  and  the  biting  mania.     Not  only  their  persons,  but  their  houses 
were  uncleanly,  even  in  the  classes  that  were  well-to-do.     Filth,  instead 
of  being  abhorred,  was  almost  sanctified."  —  Lyon  Playfair. 

5.  An  Imaginary  Conversation  on  Baths  and  Bathing.  —  "I  have 
often  amused  myself,  by  fancying  one  question  which  an  old  Roman 
emperor  would  ask,  were  he  to  rise  from  his  grave  and  visit  the  sights  of 
London  under  the  guidance  of  some  minister  of  state.     The  august  shade 
would,  doubtless,  admire  our  railroads  and  bridges,  our  cathedrals  and 
our  public  parks,  and  much  more  of  which  we  need  not  be  ashamed. 
But  after  a  while,  I  think,  he  would  look  round,  whether  in  London,  or 
in  most  of  our  great  cities,  inquiringly  and  in  vain,  for  one  class  of  build- 


20.  Give  the  quotation.     Perspiration  ? 

21.  Ablution  in  warm  climates  ?    What  advice  is  given  ? 


THE  INTEGUMENT,   OR  SKIN  65 

22.  There  is  a  maxim  by  the  chemist  Liebig,  to  the  effect, 
that  the  civilization  of  a  nation  is  high,  in  proportion  to  the 
amount  of  soap  that  it  consumes ;  and  that  it  is  low,  in  propor- 
tion to  its  use  of  perfumes.  In  some  degree,  we  may  apply 
the  same  test  to  the  refinement  of  an  individual.  The  soap 
removes  impurity;  the  perfume  covers,  while  retaining  it. 
(Bead  Notes  6  and  7.) 

ings,  which  in  his  empire  were  wont  to  be  most  conspicuous  and  splendid. 
4  And  where,'  he  would  ask,  '  are  your  public  baths  ? '  And  if  the  min- 
ister of  state  who  was  his  guide  should  answer — '  O  great  Caesar,  I  really 
do  not  know.  I  believe  there  are  some  somewhere  in  some  out-of-the-way 
place  ;  and  I  think  there  have  been  some  meetings  lately,  and  an  amateur 
concert,  for  restoring,  by  private  subscriptions,  some  baths  and  wash- 
houses  which  had  fallen  to  decay.  And  there  may  "be  two  or  three  more 
about  the  metropolis ;  for  parishes  have  power  to  establish  such  places,  if 
they  think  fit,  and  choose  to  pay  for  them  out  of  the  rates  : '  —  Then,  I 
think,  the  august  shade  might  well  make  answer  —  '  We  used  to  call  you, 
in  old  Rome,  northern  barbarians.  It  seems  that  you  have  not  lost  all 
your  barbarian  habits.  Are  you  aware  that,  in  every  city  in  the  Roman 
empire,  there  were,  as  a  matter  of  course,  public  baths  open,  not  only  to 
tne  poorest  freeman,  but  to  the  slave,  usually  for  the  payment  of  the 
smallest  current  coin,  and  often  gratuitously  ?  Are  you  aware  that  in 
Rome  itself,  millionaire  after  millionaire,  emperor  after  emperor,  built 
baths,  and  yet  more  baths';  and  connected  with  them  gymnasia  for  exer- 
cise, libraries,  and  porticoes,  wherein  the  people  might  have  shade  and 
shelter,  and  rest?  Are  you  aware  that  these  baths  were  of  the  most 
magnificent  architecture,  decorated  with  marbles,  paintings,  sculptures, 
fountains,  what  not  ?  And  yet  I  had  heard,  in  Hades  down  below,  that 
you  prided  yourselves  here  on  the  study  of  the  learned  languages.'  "  — 
Rev.  Charles  Kingsley  on  the  Air-mothers. 

6.  Care  of  the  Skin  and  Nails.  —  "  Much  ignorance  prevails  amongst 
the  public  as  to  the  use  of  soap  and  water.  Those  who  have  very  sensitive 
skins  should  use  soft  water,  for  the  face  at  all  events,  and  the  best  water, 
if  it  can  be  had,  is  rain- water  with  the  cold  taken  off  it.  Nor  is  it  every 
kind  of  soap  which  is  tolerated  by  such  persons  ;  probably  the  safest  soaps 
are,  not  those  which  are  said  to  contain,  but  those  which  really  do  contain, 
a  large  portion  of  glycerin. 

"  The  culture  of  the  nails,  which  when  perfect  constitute  so  great  a 
beauty,  is  of  much  importance  ;  but  the  tendency  is  to  injure  them  by  too 
much  attention.  The  scissors  should  never  be  used,  except  to  pare  the 
free  edges  when  they  have  become  ragged  or  too  long,  and  the  folds  of 
scarf  skin  which  overlap  the  roots  should  not,  as  a  rule,  be  touched.  The 
upper  surfaces  of  the  nails  should  on  no  account  be  touched  with  the  knife, 


22.  Liebig's  maxim  ?    What  further  Is  added  2 


66  THE  INTEGUMENT,   OR  SKIN 

23.  The  Different  Kinds  of  Baths.  —  All  persons  are  not  alike 
able  to  use  the  cold  bath.     When  the  health  is  vigorous,  a 
prompt  reaction  and  glow  upon  the  surface  will  show  that  it  is 
beneficial.     Where  this  pleasurable  feeling  is  not  experienced, 
but  rather  a  chill  and  sense  of  weakness  follows,  we  are  warned 
that  the  system  will  not,  with  impunity,  endure  cold  bathing. 
Most  persons  experience  the  best  results  when  the  water  is 
about  the  temperature  of  the  body  —  "  blood-heat." 

24.  It  should  also  be  borne  in  mind,  that  the  warm  or  hot 
bath  cannot  be  continued  so  long,  or  repeated  so  frequently,  as 
the  cold,  on  account  of  the  enervating  effect  of  unusual  heat  so 
applied  to  the  body.     For  persons  who  are  not  in  robust  health, 
one  warm,  bath  each  week  is  sufficient.     Such  persons  should 
be  careful  to  avoid  every  extreme  in  reference  to  bathing, 
clothing,  and  whatever  greatly  affects  the  action  of  the  skin. 

25.  Sea-bathing  is  even  more  invigorating  than  fresh-water 
bathing.     Those  who  cannot  endure  the  fresh  water,  are  often 
benefited  by  the  salt-water  baths.     This  may  be  accounted  for, 
in  part,  by  the  stimulant  action  upon,  the  surface,  of  the  saline 
particles  of  the  sea-water ;  but  the  exciting  scenes  and  circum- 
stances of  sea-bathing  also  exert  an  important  influence.     The 
open-air  exercise,  the  rolling  surf,  the  genial  weather,  and 
usually  the  cheerful  company,  add  to  its  intrinsic  benefits. 
(Head  Note  8.) 

as  it  is  so  often  done,  the  nail  brush  being  amply  sufficient  to  keep  them 
clean,  without  impairing  their  smooth  and  polished  surfaces."  —  People's 
Magazine. 

7.  On  Scents.  —  "  They  are  the  only  -resource  of  rnde  and  dirty  times 
against  offensive  emanations  from  decaying  animal  and  vegetable  sub- 
stances, from  undrained  and  untidy  dwellings,  from  unclean  clothes,  from 
ill-washed  skins,  and  from  ill-used  stomachs.    The  scented  handkerchief, 
in  these  circumstances,  takes  the  place  of  the  sponge  and  the  bath ;  the 
pastile  hides  the  want  of  ventilation  ;  the  otto  of  roses  seems  to  render 
the  scavenger  unnecessary  ;  and  a  sprinkling  of  musk  sets  all  other  smells 
and  stinks  at  defiance."  — Johnston. 

8.  The  Proper  Use  of  Sea-bathing.  —  "The  length  of  time  during 
which  a  person  should  remain  in  the  water  necessarily  varies  according  to 


23.  What  is  said  about  cold  bathing  ? 

24.  What  is  said  about  warm  bathing  ? 

25.  What  is  said  about  sea-bathing  ? 


THE  INTEGUMENT,   OR  SKIN  67 

26.  Time  and  Manner  of  Bathing.  —  A  person  in  sound  health 
may  take  a  bath  at  almost  any  time,  except  directly  after  a  full 
meal.     The  most  appropriate  time  is  about  three  hours  after  a 
meal,  the  noon-hour  being  probably  the  best.     For  the  cold 
bath,  taken  rapidly,  no  time  is  better  than  immediately  after 
rising.     Those  beginning  the  use  of  cold  baths  should  first  try 
them  at  70°  Fahrenheit,  and  gradually  use  those  of  a  lower 
temperature.     From  five  to  twenty  minutes  may  be  considered 
the  proper  limit  of  time  to  remain  in  a  bath ;  but  a  sensation 
of  chilliness  is  a  signal  to  withdraw  instantly,  whether  at 
home,  or  at  the  sea-side.     Two  sea-baths  may  be  taken  daily ; 
one  of  any  other  kind  is  sufficient. 

27.  The  body  should  be  warm,  rather  than  cold,  when  step- 
ping into  the  bath ;  and  after  it,  the  skin  should  be  thoroughly 
dried  with  a  coarse  towel.     It  is  best  to  continue  friction  until 
there  is  a  sensation  of  warmth  or  "  glow  "  throughout  the  entire 
surface.     This  reaction  is  the  test  of  the  good  effects  of  the 
bath.     If  reaction  is  still  incomplete,  a  short  walk  may  be 
taken,  especially  in  the  sunshine.     It  is  very  congenial,  how- 

the  age,  sex,  and  constitutional  strength  of  the  bather.    Due  regard  should 
also  be  had  to  the  state  of  the  weather  and  season  of  the  year. 

"  In  the  case  of  children,  five,  gradually  extended  to  ten  minutes  ;  of 
women,  ten  to  fifteen  minutes  ;  and  of  men,  a  quarter  of  an  hour  or  more, 
is  a  fair  average  period.  There  are  some  people,  doubtless,  to  whom 
these  periods  will  appear  insufficient,  and  who  insist  on  remaining  so  long 
in  the  water  that  their  skin  becomes  cold  and  blue,  their  teeth  begin  to 
chatter,  and  a  condition  of  general  exhaustion  comes  on ;  people,  hi  short, 
who  have  the  *  most '  for  their  money,  like  the  countryman  who  grumbled 
at  having  been  conveyed  thirty  miles  hi  about  half-an-hour  by  an  express 
train,  on  the  score  that  the  length  of  time  occupied  in  the  journey  was 
not  proportionate  to  the  fare  that  he  had  paid.  On  entering  the  water, 
the  bather  should  immerse  the  whole  of  the  body  two  or  three  times,  so 
as  to  get  the  action  of  the  shock  from  the  cold  water  distributed  over  its 
entire  surface.  There  should  be  no  hesitancy,  no  dabbling  about  with 
the  feet,  but  a  good  plunge  at  once  into  the  next  wave  that  washes  in. 
Upon  coming  out  of  the  water  the  bather  should  dry  the  body  with  good 
rough  towels,  dress  quickly,  and  take  a  brisk  walk  for  a  short  distance. 
If  there  be  any  feeling  of  exhaustion  or  nervous  depression,  a  little  food 
or  drink  should  be  taken." 


26.   What  is  said  as  to  the  time  and  manner  of  bathing  T 

87.  Condition  of  the  body  when  bathing?    Direction,  after  bathing  f 


68  THE  INTEGUMENT,   OR  SKDT 

ever,  both  to  health  and  comfort,  to  rest  for  a  short  time 
directly  after  bathing,  or  to  take  some  light  refreshment. 
This  is  better  than  severe  exercise  or  a  full  meal. 

28.  Bathing  among  the  Ancients.  —  The  Romans  and  other 
nations  of  antiquity  made  great  use  of  the  vapor-bath  as  a 
means  of  preserving  the  health,  but  more  particularly  as  a 
luxury.     Their  method  was  not  unlike  that  employed  in  some 
parts  of  Europe  at  the  present  day.     The  public  baths  of  Rome 
and  other  cities  are  among  the  grandest  and  most  interesting 
monuments  of  ancient  luxury  and  splendor ;   and  from  their 
ruins  have  been  recovered  some  of  the  most  beautiful  works 
of  art. 

29.  The  Thermae,  as  the  baths  of  Rome  were  called,  were  of 
great  extent,  built  very  substantially,  and  ornamented  at  vast 
expense.     They  were  practically  free  to  all,  the  cost  of  a  bath 
having  been  less  than  a  cent.     It  is  related  that  some  persons 
bathed  seven  times  a  day.     After  the  bath  their  bodies  were 
anointed  with  perfumed  oil.     If  the  weather  was  fine,  they 
passed  directly  from  the  Thermae  into  the  gymnasium,  and 
engaged  in  some  gentle  exercise  previous  to  taking  the  midday 
meal.     Between  two  and  three  in  the  afternoon  was  the  favor- 
ite hour  for  this  ancient  luxury.     Swimming  was  a  favorite 
exercise,  and  a  knowledge  of  it  was  regarded  as  necessary  to 
every  educated  man.     Their  common  expression,  when  speak- 
ing of  an  ignorant  person,  was,  "He  can  neither  read  nor 
swim." 

30.  The  Sun-Bath.  —  Some  also  were  accustomed  daily  to 
anoint  themselves,  and  lie  or  walk  in  apartments  arranged  for 
the  purpose,  with  naked  bodies  exposed  to  the  direct  rays  of 
the  sun.     There  is  an  interesting  allusion  to  this  practice,  in  a 
letter  of  the  younger  Pliny  to  the  historian  Tacitus,  describing 
the  destruction  of  Pompeii  by  an  eruption  of  Vesuvius.     "  My 
uncle  "  (Pliny  the  elder)  "  was  at  that  time  in  command  of  the 
fleet  at  Misenum.     On  the  24th  of  August,  about  one  in  the 
afternoon,  my  mother  desired  him  to  notice  a  cloud  which 

28.  Bathing  among  the  ancients  ?    Baths  of  Kome  ? 

29.  After  the Jbath  ?    Swimming  among  the  ancients  ? 
80.  The  sun-bath  ?    The  story  of  Pliny  ? 


THE  INTEGUMENT,   OR  SKIN  69 

seemed  of  unusual  shape  and  dimensions.  He  had  just  returned 
from  taking  the  benefit  of  the  sun,  and  after  a  cold  bath,  and  a  slight 
repast,  had  retired  to  his  study."  Then  follows  a  description 
of  the  destruction  of  Pompeii,  and  the  death  of  the  elder  Pliny. 

31.  We  may  judge  somewhat  of  the  benefits  of  the  sun,  by 
observing  the  unnatural  and  undeveloped  condition  of  plants 
and  animals  which  are  deprived  of  light.     Plants  become 
blanched  and  tender ;  the  fish  of  subterranean  lakes,  where  the 
light  of  day  never  enters,  are  undersized,  and  have  no  eyes ; 
tadpoles  kept  in  the  dark  dp  not  develop  into  frogs;   men 
growing  up  in  mines  are  sallojv,  pale,  and  deformed.     Besides 
the  well-known  effect  of  solar  light  in  tanning  the  skin,  it  also 
makes  it  thicker  and  better  able  to  resist  exposure;   though 
the  complexion  may  be  thereby  injured,  the  health  gained 
more  than  compensates  for  the  loss  of  beauty.     "To  make 
good  the  loss  of  the  lily,  where  the  sun  has  cast  his  ray,  he 
seldom  fails  to  plant  the  rose."     (Read  Notes  9  and  10.) 

32.  Clothing.*  —  In  reference  to  clothing,  we  are  far  more 
apt,  in  our  changeful  climate,  to  use  too  little  than  too  much. 

9.  Light  Influences  Growth  and  Health.  —  "I  have  several  times 
taken  two  potatoes  which  were  as  nearly  as  possible  alike,  and  placed 
one  under  a  bell-glass  through  which  the  light  could  pass,  and  the  other 
under  a  similar  cover  rendered  opaque  by  several  coats  of  black  paint. 
Sprouting  went  on  unchecked  under  the  translucent  glass,  while  it  was 
always  notably  retarded  and  sometimes  prevented  in  the  potato  under  the 
dark  glass.  Milne  Edwards,  a  distinguished  French  physiologist,  per- 
formed a  series  of  experiments  which  showed  that  tadpoles  when  deprived 
of  light  did  not  develop  into  the  frog.  I  have  several  times  repeated  his 
experiments,  and  always  with  confirmatory  results.  On  one  occasion  I 
prevented  for  one  hundred  and  twenty-five  days  the  development  of  a 
tadpole,  by  confining  it  in  a  vessel  to  which  the  rays  of  light  had  no 
access.  On  placing  it  in  a  receptacle  open  to  the  light,  the  process  of 
transformation  was  at  once  begun,  and  was  completed  in  fifteen  days. 
The  practical  application  of  these  and  similar  observations  is  this,  that 
core  should  be  taken  both  in  health  and  disease  to  insure  a  sufficient 
amount  of  sunlight  to  the  inmates  of  Houses,  and  that  it  is  impossible  to 
rear  well-formed,  strong,  and  robust  children  unless  attention  is  paid  to 
this  requirement."  —  Hammond  on  the  Influence  of  Light. 

*  Man  is  the  only  animal  that  requires  clothing ;  and  as  he  advances 


81.  Benefit  of  the  sun  ?    Effect  upon  plants  ?    Skin  ? 

82.  Direction  about  clothing  f    Exposing  limbs  of  children  ?    Clothing,  night  and  day  f 


70  THE  INTEGUMENT,   OR  SKIN 

An  aphorism  of  Boerhaave,  worth,  remembering,  if  not  of 
adopting,  is,  "  We  should  put  off  our  winter  clothing  on  mid- 
summer's day,  and  put  it  on  again  the  day  after."  He  also 
says,  "  Only  fools  and  beggars  suffer  from  the  cold ;  the  latter 
not  being  able  to  get  sufficient  clothes,  the  others  not  having 
the  sense  to  wear  them."  The  practice  of  exposing  the  limbs 
and  necks  of  young  children,  for  the  alleged  purpose  of  "  hard- 
ening "  them,  is  quite  hazardous.  It  is  not  to  be  denied  that 
some  seem  to  be  made  tough  by  the  process.  But  it  is  so  only 
with  the  rugged  children;  the  delicate  ones  will  invariably 
suffer  under  this  fanciful  treatment.  As  the  skin  is  constantly 
acting,  by  night  as  well  as  by  day,  it  is  conducive  both  to 
cleanliness  and  comfort  to  entirely  change  the  clothing  on 
retiring  for  the  night.  The  day-clothing  should  be  aired  dur- 
ing the  night,  and  the  bedding  should  be  aired  in  the  morning, 
for  the  same  reason.  (Head  Notes  11  and  12.) 

from  barbarism  to  civilization,  more  and  more  attention  is  paid  to  dress 
as  a  means  of  protection  against  cold.  As  a  rule,  more  harm  arises  from 
using  too  little  clothing  than  too  much,  especially  in  a  changeful  climate 
like  our  own. 

10.  Light  in  the  Sick-room.  —  "It  is  the  unqualified  result  of  all  my 
experience  with  the  sick,  that  second  only  to  their  need  of  fresh  air  is 
their  need  of  light ;  that,  after  a  close  room,  what  hurts  them  most  is  a 
dark  room ;  and  that  it  is  not  only  light,  but  direct  sunlight  they  want. 
You  had  better  carry  your  patient  about  after  the  sun,  -according  to  the 
aspect  of  the  rooms,  if  circumstances  permit,  than  let  him  linger  in  a 
room  when  the  sun  is  off.     People  think  that  the  effect  is  upon  the  spirits 
only.    This  is  by  no  means  the  case.     Who  has  not  observed  the  purify- 
ing effect  of  light,  and  especially  of  direct  sunlight,  upon  the  air  of  a 
room  ?    "Here  is  an  observation  within  everybody's  experience.     Go  into 
a  room  where  the  shutters  are  always  shut  (in  a  sick-room  or  a  bed-room 
there  should  never  be  shutters  shut),  and  though  the  room  be  uninhabited 
— though  the  air  has  never  been  polluted  by  the  breathing  of  human 
beings,  you  will  observe  a  close,  musty  smell  of  corrupt  air — of  air 
unpurified  by  the  effect  of  the  sun's  rays.     The  mustiness  of  dark  rooms 
and  corners,  indeed,  is  proverbial.    The  cheerfulness  of  a  room  —  the 
usefulness  of  light  in  treating  disease  —  is  all-important.    It  is  a  curious 
thing  to  observe  how  almost  all  patients  lie  with  their  faces  turned  to  the 
light,  exactly  as  plants  always  make  their  way  toward  the  light."  — 
Florence  Nightingale's  Notes  on  Nursing. 

11.  Underclothing  and  Bedding.  — All  clothing  worn  during  the  day 
should  be  removed  at  night.    A  practice  prevails  in  tropical  countries  of 
shaking  thoroughly  every  article  of  apparel  just  before  it  is  placed  on  the 


THE  INTEGUMENT,    OR  SKIN  71 

33.  Poisonous  Cosmetics.  —  The  extensive  use  of  cosmetics  for 
the  complexion  is  a  fertile  source  of  disease.  The  majority  of 
these  preparations  contain  certain  poisonous  mineral  substances, 
chiefly  lead.  The  skin  rapidly  absorbs  the  fine  particles  of 
lead,  and  the  system  experiences  the  same  evil  effects  that  are 
observed  among  the  operatives  in  lead  works  and  painters, 
namely,  "painters'  colic,"  and  paralysis  of  the  hands,  called 
"  wrist-drop." 

body.  The  motive  which  prompts  this  comes  from  the  fear  lest  a  centi- 
pede or  other  lively  and  virulent  specimen  of  natural  history  has  hid  itself 
somewhere  within  the  folds  of  the  garment.  Even  without  the  danger  of 
wearing  one's  shirt  in  conjunction  w,ith  such  an  intruder,  it  is  an  excellent 
practice  to  shake  it  and  every  other  article  of  clothing  thoroughly  before 
putting  them  on.  The  garments  worn  next  to  the  skin  should  be  changed 
before  they  become  saturated  with  the  secretions  of  the  sebaceous  glands. 
This  can  be  accomplished  by  renewing  them  twice  a  week,  though  the 
majority  of  people  only  change  them  once  in  that  period.  Combe  recom- 
mends to  wear  two  sets  of  flannels,  each  being  worn  and  aired  by  turns, 
on  alternate  days;  he  likewise  praises  a  practice  common  in  Italy, 
namely,  instead  of  beds  being  made  up  in  the  morning  the  moment  they 
are  vacated,  and  while  still  saturated  with  the  nocturnal  exhalations,  the 
bed-clothes  are  thrown  over  the  backs  of  chairs,  the  mattresses  shaken 
up,  and  the  window  thrown  open  for  the  greater  part  of  the  day.  This 
practice,  so  consonant  with  reason,  imparts  a  freshness  which  is  peculiarly 
grateful  and  conducive  to  sleep.  Florence  Nightingale,  who  never  fails 
to  speak  plainly,  says:  "  Feverishness  is  generally  supposed  to  be  a 
symptom  of  fever  ;  in  nine  cases  out  of  ten  it  is  a  symptom  of  bedding. 
A  real  patient  should  have  two  beds,  remaining  only  twelve  hours  in 
each  ;  on  no  account  to  carry  his  sheets  with  him."  —  Draper  (in  Part}. 

12.  Rules  as  to  Clothing.  —  Protection  against  Cold. — For  equal 
thicknesses,  wool  is  much  superior  to  either  cotton  or  linen,  and  should 
be  worn  for  all  underclothing.  In  cases  of  extreme  cold,  besides  wool, 
leather  or  waterproof  clothing  is  useful.  Cotton  and  linen  are  nearly 
equal. 

Protection  against  Heat.  —  Texture  has  nothing  to  do  with  protection 
from  the  direct  solar  rays  ;  this  depends  entirely  on  color.  White  is  the 
best  color ;  then  gray,  yellow,  pink,  blue,  black.  In  hot  countries,  there- 
fore, white  or  light-gray  clothing  should  be  chosen.  In  the  shade  the 
effect  of  color  is  not  marked.  The  thickness  and  the  conducting  power 
of  the  material  are  the  conditions  (especially  the  former)  which  influ- 
ence heat. 

The  body  should  not  only  be  so  protected  by  its  covering  as  to  be  kept 
from  rain  and  damp,  but  the  clothing  must  be  so  ventilated  that  the 


88.  Cosmetics?    Painters' colic  ? 


72  THE  INTEGUMENT,   OR  SKIN 

34.  Certain  hair-dyes  also  contain  lead,  together  with  other 
noxious  and  filthy  ingredients.  These  do  not  work  as  great 
harm  as  the  cosmetics,  since  they  are  purposely  kept  away 
from  the  skin;  but  they  rob  the  hair  of  its  vitality.  Eye- 
washes, too,  are  made  from  solutions  of  lead,  and  many  an  eye 
has  been  ruined  by  their  use.  They  deposit  a  white  metallic 
scale  on  the  surface  of  the  eye,  which,  when  in  front,  perma- 
nently blurs  the  sight. 

emanations  from  the  skin  shall  not  accumulate.  The  wearing  of  the 
un ventilated  beaver  hat,  or  fur  cap,  is  a  ready  method  of  suppressing 
the  natural  growth  of  the  hair,  and  of  causing  the  retention  of  that  effete 
epithelial  scale  commonly  called  scurf,  or  dandruff.  The  wearing  of 
tightly  fitting  waterproof  coats  cannot  be  habitually  practiced  without 
danger  to  the  wearer ;  the  very  painful  and  troublesome  ailment,  rheuma- 
tism, has  in  many  persons  been  produced  by  this  manner  of  locking  in 
the  excretions  of  the  surface.  —  Dr.  B.  W.  Richardson. 


THE  INTEGUMENT,   OR  SKIN 


73 


SKIN 


Epidermis 


Rete 
Mucosum 


Dennis 


Glands 


Nails 


PERSPIRA- 
TION .... 


Hairs 


Composition 


Quantity 


Uses 


Ducts 


TOPICAL  OUTLINE 

Composed  of  flattened  scales. 
Horny  and  transparent. 
Impermeable  to  rtuids. 
No  nerves  or  blood-vessels. 
Simply  protective. 

Surface  continually  removed  by  friction. 
Softer  aiid  less  transparent. 
Contains  pigment  cells, 
(firt's  colour  to  the  skin. 
Fibres  of  connective  and  elastic  tissues. 
Numerous  blood-vessels  and  nerves. 
Drawn  up  into  papillae. 
I  Fat-cells  in  deeper  portion. 

Situated  deep  in  the  dermis. 
Consist  of  coiled  tubes. 
Surrounded    by    capillary    net- 
works. 

Nearly        straight 

Sweat    .  .  -j  through  dermis. 

Twisted     in      epi- 
dermis. 

Open   at   the    sur- 
face (pores). 
Secrete  the  perspiration. 
Connected  with  hairs. 
_  ,  Secrete  an  oily  fluid. 

I  Sebacec  ,  Discharged  into  the 

I      follicles. 
I  Lubricates  the  hair 
I     and  skin. 
Thick,  horny  plates  of  epidermis. 

f  Only  where  adherent  to  skin. 
Growth .  .  <  Above,  below,  and  behind  at  the 

root. 
Pushed  forward  by  growth  behind. 

f  Interior    medullary  portion   or 
Shaft .  .  J     pith. 

|  Outer  cortical  or  fibrous  portion. 
i  Bulb-like  at  lower  extremity. 
Root  .  .  .  -j  Imbe(jded  in  follicle. 
Pushed  outward  by  growth  at  the  base. 
Glands  — sebaceous  (see  above). 
Muscles— tend  to  erect  the  hair  by  their  con- 
traction. 
Water. 

Salts  — especially  common  salt. 
Little  carbonic  acid  gas  in  solution. 
f  Average  about  two  pounds  a  day. 
\  Greater  in  summer  than  in  winter. 
[  Greater  during  activity, 
f  Removal  of  waste  matter, 
j  Tends  to  reduce  the  temperature  of  the  body 
I     by  its  evaporation. 


Secretion 


74  THE  INTEGUMENT,   OR  SKIN 


•       QUESTIONS    FOR   TOPICAL    REVIEW 

PAGE 

1.  What  are  the  characteristics  of  the  skin,  and  what  office  does  it 

perform  ? 56 

2.  What  can  you  state  of  the  structure  of  the  skin  ? 56 

3.  Describe  the  cuticle  and  tell  its  use 56,  57 

4.  Describe  the  cutis  or  true  skin  and  tell  its  use 57,  58 

5.  What  can  you  state  of  the  nature  and  growth  of  the  nail  ? 58 

6.  Explain  growth  of  the  hair  ? 59 

7.  Of  the  nature  and  growth  of  the  hair  ? 59 

8.  Of  the  offices  performed  by  the  nails  and  hair  ? 59 

9.  What  is  an  Albino  ? 60 

10.  How  is  the  difference  in  complexion  in  different  persons  accounted 

for? 60 

11.  How  is  the  presence  of  freckles  accounted  for  ? 60 

12.  How  does  Nature  provide  a  dressing  for  the  hair  ? 60,  61 

13.  What  is  the  composition  of  perspiration  ? 62 

14.  What  other  service  do  the  sebaceous  glands  perform  ? 61 

15.  State  what  you  can  of  the  perspiratory  glands  and  their  number?. .  61,  62 

16.  What  is  the  difference  between  sensible  and  insensible  perspiration  ?       62 

17.  State  the  uses  and  importance  of  perspiratiop  ? 62,  63 

18.  What  impurities  gather  naturally  on  the  skin  ? 64 

19.  What  are  the  effects  of  stopping  perspiratory  action  ? 62,  63 

20.  Repeat  what  is  said  of  the  importance  of  bathing  ? 64,  65 

21.  Different  kinds  of  baths  for  different  individuals ? 66 

22.  When  should  we  indulge  in  cold,  warm,  and  sea-bathing? 67 

23.  What  is  the  effect  in  each  case  ? 67 

24.  What  directions  are  given  as  to  the  time  and  manner  for  bathing?.        67 

25.  What  is  related  of  bathing  among  the  ancients  ? 68 

26.  Directions  after  the  bath  ? 68 

27.  What  is  related  to  show  the  antiquity  of  sun-bathing  ? 68,  69 

28.  What  are  the  effects  of  sun-bathing  ? 69,  70 

29.  What  directions  are  given  in  relation  to  clothing  the  body? 69,  70 

30.  What  can  you  state  of  poisonous  cosmetics  ? » 71,  72 

31.  Of  hair-dyes  and  eye-washes  ? 72 


CHAPTER  IV 

THE    CHEMISTRY    OF    FOOD 

The  Source  of  Food  —  Inorganic  Substances —  Water — Salt  —  Lime  — 
Iron — Organic  Substances  —  Albumen,  Fibrin,  and  Caseine — The 
Fats  or  Oils —  The  Sugars,  Stanch,  and  Gum  —  Stimulating  Substances 
—  Necessity  of  a  Regulated  Diet 

1.  The  Source  of  Food.  —  The  term  food  includes  all  those 
substances,  whether  liquid  or  solid,  which  are  necessary  for 
the  nourishment  of  the  body.     The  original  source  of  all  food 
is  the  earth,  which  the  poet  has  fitly  styled  the  "  Mother  of  all 
living."     In  her  bosom,  and  in  the  atmosphere  about  her,  are 
contained  all  the  elements  on  which  life  depends.     But  man 
is  unable  to   obtain   nourishment   directly  from   such  crude 
chemical   forms   as  he  finds  in  the  inorganic  world.     They 
must,  with  a  few  exceptions,  be  prepared  for  his  use,  by  being 
transformed  into  new  and  higher  combinations,  more  closely 
resembling  the  tissues  of  his  own  body. 

2.  This  transformation  is  effected,  first,  by  the  vegetable 
world.     But  all  plants  are  not  alike  useful  to  man,  while  some 
are  absolutely  hurtful.     Accordingly,  he  must  learn  to  discrimi- 
nate between  that  which  is  poisonous  and  that  which  is  life- 
supporting.     Again,  all  parts  of  the  same  plant  or  tree  are  not 
alike  beneficial :  in  some,  the  fruit ;  in  others,  the  leaves ;  and 
in  others,  the  seeds  only  are  sufficiently  refined  for  his  use. 
These  he  must  learn  to  select ;  he  must  also  learn  the  proper 
modes  of  preparing  each  kind  for  his  table,  whether  by  cooking 
or  other  processes.     (Read  Note  1.). 

1.   The  Circle  of  Organic  Life.  —  "  Man,  as  an  animal,  is  chemically  an 
oxidizing  agent,  reducing  again  to  primitive  forms  the  principles  built  up 


1.  The  term  fowl  ?    Source  of  food  ?    Need  of  preparing  food  ? 

2.  Usefulness  and  hurtfulness  of  plants?    What  then  must  man  do  ?    Parts  of  the  same 
plant  or  tree  ? 


76  THE  CHEMISTRY  OF  FOOb 

3.  Again,  certain  forms  of  the  vegetable  creation  which  are 
unfit,  in  their  crude  state,  for  man's  food,  and  which  he  rejects, 
are  chosen  as  food  by  some  of  the  lower  animals,  and  are,  by 
Them,  made  ready  for  his  use.  Thus  the  bee  takes  the  clover, 
that  man  cannot  eat,  and  from  it  collects  honey.  The  cattle 
eat  the  husks  of  corn  and  the  dried  grass,  that  are  by  far  too 
coarse  for  man,  and  in  their  own  flesh  convert  them  into  tissues 
closely  resembling  his  muscular  tissue.  In  this  way,  by  the 
aid  of  the  transforming  processes  of  the  vegetable  and  animal 
creations,  the  simple  chemical  elements  of  the  mineral  kingdom 
are  elaborated  into  our  choice  articles  of  food.  (Read  Note  2.) 

by  the  vegetable  world,  and  taken  in  by  him  either  directly  as  vegetables, 
or  indirectly  in  the  shape  of  the  material  of -other  animals.  Without 
vegetable  lite  animals  could  not  exist,  and  never  could  have  existed  ;  side 
by  side  they  grow  and  flourish,  indispensable  to  each  other's  existence ; 
the  tree  breaking  up  the  exhaled  carbonic  acid  of  the  animal  —  the  carbon 
being  stored  up  in  its  increasing  mass  —  while  the  oxygen  is  returned 
again,  free  and  uncombined,  to  the  atmosphere  for  the  respiratory  needs 
of  the  animal  world.  Hound  and  round  go  the  elementary  bodies  in 
ceaseless  change  of  form,  nevertheless  never  more  than  they  were  at  first 
and  will  be  at  the  last  —  the  atomic  material  of  this  planetary  sphere 
being  ever  absolutely  the  same  in  amount.  The  material  of  the  bodies  of 
Saul  and  his  sons,  when  burnt  by  the  men  of  Israel  after  their  ignominious 
exposure  at  Bethshan,  in  consequence  of  their  defeat  on  Mount  Gilboa, 
ane  circulating  amongst  us  still;  it  served  others  before  them,  and  has 
formed  part  of  thousands  since.  It  is  quite  within  the  bounds  of  chemical 
possibility  that  some  of  the  atoms  contained  in  the  fated  apple  of  Eve, 
may  have  lain  in  the  material  of  the  apple  which  revealed  to  Newton  the 
law  of  gravitation."  —  Fothergill  on  the  Maintenance  of  Health. 

2.  The  Food  Circle  in  Nature.  —  "  There  are  some  ultimate  elements 
in  flesh  as  in  flour,  the  same  in  animals  as  in  vegetables.  The  vegetable 
draws  food  from  the  soil  and  from  the  air,  and  being  fully  matured,  it  or 
some  part  of  it  is  eaten  by  the  animal.  But  in  completing  the  circle,  the 
vegetable  receives  and  thrives  upon  the  animal  itself,  in  whole  or  in  part, 
or  the  refuse  which  it  daily  throws  off.  The  very  bones  of  an  animal  ara 
by  nature  or  man  made  to  increase  the  growth  of  vegetables  and  really  to 
enter  into  their  structure  ;  and  being  again  eaten,  animals  may  be  said 
to  eat  their  own  bones,  and  live  on  their  own  flesh.  Hence  there  is  not 
only  an  unbroken  circle  in  the  production  of  food  from  different  sources, 
but  even  the  same  food  may  be  shown  to  be  produced  from  itself.  Surely 
this  is  an  illustration  of  the  fable  of  the  young  Phoenix  arising  from  the 
ashes  of  its  parent."  — Edward  Smith  on  Foods. 


8.  Certain  forms  of  vegetable  creation  ?    Example  of  the  bee  f    Cattle  ?    The  Inference  ? 


THE  CHEMISTRY  OF  FOOD  77 

4.  Inorganic  Substances.  —  The  substances  we  use  as  food 
are  classified  as  organic  and  inorganic.     By  organic  substances 
are  meant  those  derived  from  living  forms,  such  as  vegetables 
and  animals.     Inorganic  substances  are  those  simpler  inani- 
mate forms  which  belong  to  the  mineral  kingdom.     The  former 
alone  are  commonly  spoken  of  as  food;  but  the  latter  enter 
very  largely  into  the  constitution  of  the  body,  and  must  there- 
fore be  present  in  our  food.    With  the  exception  of  two  articles 
—  water  and  common  salt  —  these  substances  enter  the  system 
only  when  blended  with  organic  substances. 

5.  Water.  —  Water,  from  a  physiological  point  of  view,  is 
the  most  important  of  all  the  articles  of  food.     It  is  every- 
where found  in  the  body,  even  in  the  bones  and  the  teeth.     It 
has  been  computed  that  as  large  a  proportion  as  two-thirds  of 
the  body  is  water.    The  teeth,  the  densest  of  the  solids  in  the 
human  system,  contain  'ten  per  cent,  of  water.     The  muscles, 
tendons,  and  ligaments  are  more  than  half  water;   for  it  is 
found  that  they  lose  more  than  half  their  weight  when  dried 
with  moderate  heat.     But  it  is  in  the  fluids  of  the  body  that 
water  is  found  most  abundantly.     It  gives  to  them  the  power 
of  holding  a  great  variety  of  substances  in  solution,  and  is  the 
great  highway  by  which  new  supplies  are  conveyed  to  the  point 
where  they  are  required,  and  by  which  old  particles  of  matter, 
that  have  served  their  uses,  are  brought  to  the  outlets  of  the 
body  to  be  thus  removed  from  the  system.    (Bead  Notes  3  and  4.) 

3.  The  Only  Natural  Drink.  —  "  Water  is  the  natural  drink  of  man, 
as  it  is  of  all  organized  beings.  It  enters  more  largely  into  his  compo- 
sition than  any  other  substance,  giving  liquidity  to  the  blood,  moisture  to 
all  the  tissues,"  and  serving  as  the  great  solvent  of  the  body ;  not  less 
than  two-thirds  of  its  weight  being  of  that  element.  It  seems  as  if  all 
organic  beings  were  so  much  "organized  water."  "Soft  water  is  more 
wholesome  than  hard,  though  water  moderately  hard  is  not  perceptibly 
injurious.  When  very  hard,  a  part  of  the  salts  of  lime  can  readily  be 
precipitated  by  boiling.  As  a  rule,  spring  and  well-waters,  if  brought 
from  deep  fountains,  are  better  and  more  wholesome  than  running 


4.  What  classification  ?    Define  organic  substances.    Inorganic.    Organic,  how  spoken 
of?    The  inorganic  ?    Water  and  salt  ? 

5.  Water  in  physiology  ?    Where  found  ?    Computation  ?    Water  in  the  teeth  f    Mus- 
cles, tendons,  and  ligaments  ?    How  ascertained  ?    Water  in  the  fluids  of  the  body  f    What 
is  the  advantage  ? 


78  THE  CHEMISTRY  OF  FOOD 

6.  Man  can  remain  a  longer  time  without  solid  food  than 
without  water.     He  may  be  deprived  of  the  former  for  ten  or 
twelve  hours  without  great  suffering,  but  deprivation  of  water 
for  the  same  length  of  time  will  produce  both  severe  pain  and 
great  weakness.     The  food  should  contain  not  less  than  two 
parts  of  water  to  one  of  solid  nutriment.     Water  constitutes 
the  great  bulk  of  all  our  drinks,  and  is  also  a  large  constituent 
of  the  meats,  vegetables,  and  fruits  which  come  upon  the  table. 
Fruits,  especially,  contain  it  in  great  abundance,  and,  in  their 
proper  season,  furnish  most  agreeable  and  refreshing  supplies 
of  the  needed  fluid. 

7.  Common  Salt.  —  Salt,  or  sodium  chloride,  as  an  article  of 
food,  is  obtained  chiefly  from  the  mineral  kingdom ;  although 
plants  contain  it  in  small  quantities.,  and  it  is  also  found  in  the 
tissues  of  nearly  all  animals  used  as  food.     In  the  human  body 
it  is  an  ingredient  of  all  the  solids  and  fluids.     The  importance 

streams.  Well-water,  in  towns  and  cities,  unless  brought  from  a  great 
depth,  is  wholly  unfit  for  drinking  and  cooking.  The  immense  quantity 
of  organic  matter  which  permeates  every  inch  of  the  soil,  for  many  feet  in 
depth,  precludes  the  possibility  of  water  passing  through  it  without  being 
corrupted.  Kiver  water,  polluted  by  sewers,  is  as  disgusting  to  the  senses 
as  it  is  destructive  to  health.  The  notion  that  impure  water  can  be 
rendered  more  wholesome  by  icing  it  is  an  erroneous  one.  Ice-cold 
drinks  in  summer,  while  the  body  is  heated,  are  capable  of  producing 
lifetime  disease,  and  even  instant  death."  — J.  R.  Black  on  the  Ten  Laws 
of  Health. 

4.  The  Sustaining  Power  of  Water.  —  "Water  is  the  most  reliable 
and  grateful  drink  for  man.  Nature  has  many  admixtures  in  the  juices 
of  fruits,  but  none  so  satisfying  to  excessive  thirst  as  pure  water.  It  will 
even  prolong  life  when  nutritious  food  is  not  taken,  as  we  have  a  well- 
known  instance,  recorded  by  Dr.  McNaughton,  in  the  transactions  of  the 
Albany  Institute  of  New  York  for  1836.  The  case  was  that  of  a  man 
who  lived  upon  water  alone  for  fifty -three  days.  This  he  did  while  labor- 
ing under  some  delusion  which  impelled  him  to  abstain  from  all  ordinary 
nourishment  —  water  alone  could  he  be  induced  to  partake  of.  His 
strength  was  tolerably  well  sustained  during  the  first  six  weeks  ;  he  was 
able,  in  fact,  to  go  out  of  doors  ;  and  even  on  the  day  of  his  death  he  was 
able  to  sit  up  in  bed."  —  Dr.  James  Knight. 


6.  Length  of  time  man  can  do  without  food  or  water  ?    Give  the  comparison.    Bulk  of 
drinks  ?    Constituent  of  meats,  etc.  ?    Fruits  ? 

7.  Salt,  how  obtained?    Where  found?    In  the  human  body?    Importance  of  salt? 
What  else  can  you  state  of  the  value  of  salt  ?  , 


THE  CHEMISTRY  OF  FOOD  79 

of  salt  to  animal  life  in  general,  is  shown  by  the  great  appetite 
for  it  manifested  by  domestic  animals,  and  also  by  the  habitual 
resort  of  herds  of  wild  beasts  to  the  "salt-licks"  or  springs. 
In  those  parts  of  the  world  where  salt  is  obtained  with  diffi- 
culty, man  places  a  very  high  price  upon  it. 

8.  Experiments  upon  domestic  animals  show  that  the  with- 
drawal of  salt  from  their  food  not  only  makes  their  hides 
rough  and  causes  the  hair  to  fall  out,  but  also  interferes  with 
the  proper  digestion  of  food.  If  it  be  withheld  persistently, 
they  become  entirely  unable  to  appropriate  nourishment,  and 
die  of  starvation.  (Bead  Note  5.) 

5.  Of  Salt.  - 

"Salt-cellars  ever  should  stand  at  the  head 
Of  dishes,  wheresoe'er  a  table's  spread. 
Salt  will  all  poisons  expurgate  with  haste, 
And  to  insipid  things  impart  a  taste. 
The  richest  food  will  be  in  great  default 
\)f  taste,  without  a  pinch  of  sav'ry  salt. 
Yet  of  salt  meats,  the  long-protracted  use 
Will  both  our  sight  and  manhood,  too,  reduce  ;~ 
On  tables  salt  should  stand  both  first  and  last, 
Since,  in  its  absence-,  there  is  no  repast." 

—  The  Code  of  the  School  of  Salernum. 

"Animals  will  travel  long  distances  to  obtain  salt.  Men  will  bar- 
ter gold  for  it ;  indeed,  among  the  Gallas  and  on  the  coast  of  Sierra 
Leone,  brothers  will  sell  their  sisters,  husbands  their  wives,  and  parents 
their  children  for  salt.  In  the  district  of  Accra,  on  the  gold  coast  of 
Africa,  a  handful  of  salt  is  the  most  valuable  thing  upon  earth  after  gold, 
and  will  purchase  a  slave  or  two.  Mungo  Park  tells  us  that  with  the 
Mandingoes  and  Bambaras  the  use  of  salt  is  such  a  luxury  that  to  say  of 
a  man,  '  he  flavors  his  food  with  salt,1  it  is  to  imply  that  he,  is  rich  ;  and 
children  will  suck  a  piece  of  rock-salt  as  if  it  were  sugar.  No  stronger 
mark  of  respect  or  affection  can  be  shown  in  Muscovy,  than  the  sending 
of  salt  from  the  tables  of  the  rich  to  their  poorer  friends.  In  the  book  of 
Leviticus  it  is  expressly  commanded  as  one  of  the  ordinances  of  Moses, 
that  every  oblation  of  meat  upon  the  altar  shall  be  seasoned  with  salt, 
without  lacking ;  and  hence  it  is  called  the  Salt  of  the  Covenant  of  God. 
The  Greeks  and  Romans  also  used  salt  in  their  sacrificial  cakes ;  and  it 
is  still  used  in  the  services  of  the  Latin  church  —the  lparva  mica,'  or 
pinch  of  salt,  being,  in  the  ceremony  of  baptism,  put  into  the  child's 
mouth,  while  the  priest  says,  '  Receive  the  salt  of  wisdom,  and  may  it  be 


8.  Experiments  upon  animals  ? 


80  THE  CHEMISTRY  OF  FOOD 

9.  Salt  is  usually  taken  into  the  system  in  sufficient  quantities 
in  our  food.     Even  the  water  we  drink  often  has  traces  of  it. 
The  habitual  use  of  much  salt  in  cooking,  or  as  a  seasoning  at 
the  table,  is  not  wise ;  and  while  it  may  not  lead  to  consump- 
tion, as  some  writers  declare^  it  is  a  tad  habit  in  itself,  and 
leads  to  the  desire  for  other  and  more  injurious  condiments. 

10.  Lime.  —  This  is  the  mineral  substance  which  we  have 
spoken  of  before  as  entering  very  largely  into  the  composition 
of  the  bones.     It  is  the  important  element  which  gives  solidity 
and  permanence  to  the  framework  upon  which  the  body  is 
built.     Calcium  tri-phosphate,  or  "bone-earth,"  is   the   chief 
ingredient  of  the  bones  and  teeth,  but  is  found  in  the  carti- 
lages and  other  parts  of  the  body  in  smaller  quantities.     (Read 
Note  6.) 

a  propitiation  to  thee  for  eternal  life.'  Everywhere,  and  almost  always, 
indeed,  it  has  been  regarded  as  emblematical  of  wisdom,  wit,  and  immor- 
tality. To  taste  a  man's  salt,  was  to  be  bound  by  the  rites  of  hospitality  ; 
and  no  oath  was  more  solemn  than  that  which  was  sworn  upon  bread  and 
salt.  To  sprinkle  the  meat  with  salt  was  to  drive  away  the  devil ;  and  to 
this  day,  among  the  superstitious,  nothing  is  more  unlucky  than  to  spill 
the  salt."  — Letheby  on  Food. 

6.  Phosphate  of  Lime  and  other  Inorganic  Substances.  —  "All  food 
contains  certain  saline  substances.  If  we  burn  a  portion  of  the  flesh  of 
any  animal,  we  may  drive  off  the  carbon,  oxygen,  hydrogen,  and  nitrogen, 
and  '  ashes '  are  left.  These  ashes  are  the  saline  and  mineral  (inorganic) 
constituents  of  the  animal.  They  exist  in  the  blood  and  tissues,  and  are 
as  essential  to  the  life  of  the  animal  as  those  other  elements  which  were 
expelled  by  heat.  Like  the  latter,  they  are  constantly  being  used  up  and 
carried  off  from  the  body,  and  like  them  must  be  replaced  by  means 
of  our  food.  Cooking,  especially  boiling,  tends  to  dissolve  away  some  of 
these  salts,  and  care  should  be  taken  to  supply  them  by  means  of  uncooked 
food,  as  fresh  vegetables  and  fruits  ;  milk  also  contains  them.  One  of 
the  most  important  of  these  inorganic  substances  is  phosphate  of  lime, 
or  '  bone- earth,'  as  it  is  called,  from  the  fact  that  about  forty  per  cent,  of 
healthy  bone  is  made  up  of  it.  When  it  is 'deficient,  th'e  bones  are  soft 
and  are  liable  to  be  bent  by  the  actions  of  the  muscles  attached  to  them, 
and  a  permanent  deformity  may  be  the  consequence.  This  form  of  lime 
is  contained  in  wheat,  barley,  oats,  and  rye,  and  from  these  sources  the 
chief  supply  of  it  is  derived.  These  plants  require  phosphate  of  lime  for 


9.  Salt,  how  taken  Into  the  system  ?    Its  use  in  cooking  ?    Consumption  ? 
10.  Lime  in  the  bones  ?    What  does  it  impart  ?    Chief  ingredient  of  the  bones  and  teeth  ? 
Where  else  found  ? 


THE  CHEMISTRY  OF  FOOD  81 

11.  How  does  this  substance  find  its  way  into  the  body? 
Meat,  milk,  and  other  articles  obtained  from  the  animal  king- 
dom contain  it,  and  it  is  abundantly  stored  away  also  in  the 
grains  from  which  our  bread  is  made  —  in  wheat,  rye,  and 
Indian  corn.     In  early  life,  while  the  body  is  growing,  the 
supplies  of  this  substance  should  be  carefully  provided.     The 
evil  effects  of  the  deprivation  of  it  are  too  often  and  painfully 
evident  in  the  softening  of  the  bones,  and  in  the  predisposition 
to  curvature  of  the  spine  —  deformities  which  are  most  deplor- 
able and  which  continue  through  life. 

12.  Iron.  —  This  substance  is  probably  the  most  abundant 
and  widely  diffused  of  the  metals.     It  is  found  in  most  of 
the  vegetables,  and  is  a  very  important  component  of  animal 
tissues.     It  enters  into  the  composition  of  human  blood  in 
about  one  part  per  thousand.     Ordinarily,  the  food  conveys  to 
the  system  enough  iron  for  its  use,  but  it  must  sometimes  be 
introduced  separately  as  a  remedy,  especially  after  great  loss 
of  blood,  or  after  some  wasting  disease.     Under  its  influence 
the  blood  seems  to  be  rapidly  restored,  and  a  natural  color  of 
the  lips  and  skin  replaces  the  pallor  caused  by  disease. 

13.  Other  Inorganic  Substances.  —  In  addition  to  the  sub- 
stances mentioned,  the  mineral  kingdom  supplies  compounds 
of  soda,  potash,  and  magnesia,  which  are  essential  for  the  use 
of  the  body.     They  occur  in  small  quantities  in  the  body,  and 
enter  it  in  combination  with  the  various  articles  of  diet. 

14.  Organic  Substances.  — These  substances  are  derived  from 
the  vegetable  and  animal  creations.     They  comprise  all  those 

their  growth  and  the  perfecting  of  their  grains ;  hence  it  is  supplied 
artificially  by  the  farmer.  A  diet  deficient  in  substances  yielding  the 
phosphate  of  lime  is  injurious  to  man,  and  should  be  avoided.  Its 
presence  in  wheat-flour  accounts  in  part  for  the  fact  that  our  ordinary 
loaf  of  bread  makes  so  good  a  *  staff  of  life,'  and  that  it  is,  and  has  been, 
so  widely  used  as  an  article  of  food  by  the  strongest  and  most  vigorous 
races  of  mankind."  —  Lankester's  Manual. 


11.  How  does  lime  find  its  way  into  the  body  ?    Early  life?    Effect  of  its  deprivation  ? 

12.  Iron,  its  abundance  and  diffusion  ?    Where  found  ?    What  part  of  the  blood  is  it  f 
How  supplied  to  the  system  ?    In  case  of  loss  of  blood  or  wasting  disease  ? 

13.  Soda,  potash,  and  magnesia  ?    How  do  they  occur  ? 

14.  Organic  substances,  whence  derived  ?    What  do  they  comprise  ?    Groups  ? 


82  THE  CHEMISTRY  OF  FOOD 

articles  which  are  commonly  spoken  of  as  "  food,"  and  which 
are  essential  to  sustain  the  body  in  life  and  strength.  They 
are  divided  into  three  groups,  namely :  the  Albuminoid  sub- 
stances, the  Fats,  and  Sugars. 

15.  The  Albuminoids. — This  class  includes  three  important 
nutritive  substances  —  (1)  Albumen,  which  gives  it  its  name ; 
(2)  Fibrin,  including  gluten;    and   (3)    Caseine.     These   com- 
pounds constitute  a  large  part  of  the  human  body,  and  the 
food  contains  them  in  proportionally  large  quantities.     Their 
importance  is  so  great,  and  the  system  so  promptly  suffers 
from  their  absence,  that  they  have  been  styled  the  "nutritious 
substances."     The  properties  which  they  hold  in  common  are, 
that  they  do  not  crystallize,  and  have  a  jelly-like  form,  except 
when  heat  is  applied  to  them,  when  they  harden,  or  coagulate. 

16.  They  likewise  decompose,  or  putrefy,  under  the  influence 
of  warmth  and  moisture.     Hence  the  decay  of  all  dead  animal 
tissues.     Cold   arrests   this   process.     It  is  well  known  that 
milk,  eggs,  and  the  like,  "  keep "  much  longer  in  winter  than 
at  other  seasons.     The  bodies  of  elephants,  caught  in  the  ice 
many  hundred  years  ago,  are  occasionally  borne  by  the  icebergs 
to  the  coast  of  Siberia,  completely  frozen,  but  preserved  almost 
perfectly  in  form  and  liinb. 

17.  Albumen  exists  in  milk,  meat,  the  grains,  and  the  juices 
of  many  plants;  but  the  purest  form  is  obtained  from  the 
white  of  egg.     When  we  consider  that  an  egg  is  composed 
chiefly  of  albumen  and  water  —  namely,  six  parts  in  seven ; 
and  when  we  also  consider  the  numerous,  diverse,  and  complex 
tissues  —  the  muscles,  bones,  internal  organs,  bill,  claws,  and 
feathers  —  with  which  the  chick  is  equipped  on  leaving  his 
shell,  we  are  impressed  with  the  importance  of  these  apparently 
simple  constituents  of  the  food  and  body.     (Bead  Note  7.) 

7.   Weight  and  Health. —  "The  weight  of  the  body  is  very  generally 
assumed  to  be  an  infallible  index  or  proof  of  the  maintenance  of  a  healthy 


15.  The  Albuminoid  class  includes  what?     These  compounds  constitute  what?    The 
food  ?  Their  importance  ?    Their  properties  ? 

16.  Decomposition?    Effect  of  cold  ?    Illustrations?    Elephants? 

17.  In  what  substances  does  albumen  exist  ?    What  further  is  said  of  the  egg  ? 


THE  CHEMISTRY  OF  FOOD      .  83 

18.  Fibrin  is  derived  from  meats,  and  exists  in  the  blood 
both  of  man  and  the  lower  animals.     Gluten,   or  vegetable 
fibrin,  resembles  closely  true  fibrin,  and  is  abundantly  furnished 
in  wheat  and  other  grains  from  which  flour  is  commonly  made. 
Animal  fibrin  coagulates  spontaneously  when  it  is  removed 
from  the  body,  and  thus  causes  the  "  clotting  "  of  the  blood. 

19.  Caseine  is  the  curdy  ingredient  of  the  milk,  and  a  highly 
important  food-substance.     Its  coagulation  in  milk  takes  place 
not  from  heat,  but  by  the  addition  of  an  acid,  and  also  when 
milk  becomes  sour  from  exposure  to  the  air.     It  is  commonly 
effected,  however,  by  introducing  a  piece  of  rennet,  a  prepara- 
tion made  from  a  calf's  stomach.     The  curds,  or  caseine,  may 
then  be  separated  from  the  ivhey,  and  made  into  cheese,  by 
pressing  it  sufficiently  to  drive  off  the  water. 

20.  The  Fats  or  Oils.  —  This  is  the  second  group  of  organic 
foods.     Those  which  are  more  solid  are  called  fats;  the  more 
fluid  ones  are  the  oils.     Oleaginous  substances  are  supplied  in 
both  animal  and  vegetable  food;  but,  from  whatever  source 
derived,  they  are  chemically  much  alike.     They  are  insoluble 
in  water,  and  yet  they  unite  readily  with  the  watery  fluids  of 
the  body,  and  are  by  them  conveyed  to  its  various  parts  for 
their  nourishment.     This  is  due  to  their  property  of  "  emulsi- 
fying ; "  that  is,  they  are  held  in  suspension,  in  a  finely  divided 
state,  in  water.     Ordinarily  milk  is  an  example  of  an  emulsion. 

condition  of  the  body  ;  and  that  food  which  keeps  up  the  weight  has  been 
regarded  as  satisfactory  and  nutritious.  But  this  is  not  always  a  safe 
judgment,  owing  to  the  property  in  water  from  innutritious  food  to  make 
good  the  loss  of  w.eight  caused  by  the  withdrawal  of  albumen  and  fat. 
The  weight  may  remain  the  same,  while  we  are  4  losing  flesh.'  Fat, 
also,  may  increase  in  badly  nourished  people,  while  the  more  essential 
element  of  albumen  is  diminishing  ;  the  fact  being  that  the  badly  fed  are 
not  always  lighter  than  those  who  are  well  nourished.  And  further,  the 
feeling  of  satisfaction  after  eating  is  deceptive ;  the  Irish  peasant  who 
consumes  ten  pounds  of  potatoes  in  a  day  feels  quite  satisfied,  but  is  in 
reality  badly  nourished  by  his  diet  containing  three-fourths  water."  — 
Prof.  Voitj  of  Munich. 

18.  Fibrin,  gluten,  clotting  of  the  blood  ? 

19.  Caseine  ?    Its  coagulation  ?    Effect  of  rennet  ?    Making  of  cheese  ? 

20.  What  are  the  fats  ?    The  oils  ?    How  supplied  ?    How  alike  ?    Emulsifying  ?    Ex- 
ample ?    How  do  we  know  it  ? 


84  THE  CHEMISTRY  OF  FOOD 

We  know  that  it  contains  fat,  for  butter  is  obtained  from  it ; 
and,  under  the  microscope,  the  minute  oil-globules  may  be 
distinctly  seen. 

21.  In  our  country  and  climate,  and  also  in  colder  climates, 
fatty  articles  of  food  are  principally  derived  from  the  animal 
creation,  such  as  meat  or  flesh,  milk  and  butter.     But  most  of 
the  bread-stuffs  contain  more  or  less  fat  or  oil  —  Indian  meal 
as  much  as  nine  parts  in  a  hundred. 

22.  Among  persons  living  in  cold  climates,  the  appetite  for 
oleaginous  food  is  especially  eager ;  and  they  require .  large 
quantities  of  it  to  enable  them  to  resist  the  depressing  influ- 
ences of  cold.     Since  vegetation  is  scanty  and  innutritious,  and 
the  waters  of  the  frozen  regions  abound  in  animal  life,  they 
must  rely  wholly  upon  a  diet  derived  from  the  latter  source. 
The  Esquimau  consumes  daily  from  ten  to  fifteen  pounds  of 
meat  or  blubber,  a  large  proportion  of  which  is  fat.     The 
Laplander  will  drink  train-oil,  and  regards  tallow-candles  as  a 
great  delicacy.    In  hot  climates,  on  the  contrary,  where  flourish 
the  olive  and  the  palm,  this  kind  of  food  may  be  obtained 
from  vegetable  sources  in  abundant  quantities.     (Read  Notes 
8  and  9.) 

8.  The  Necessity  of  Fat  in  the  Food  of  Children.  —  "  Children  who 
dislike  fat  cause  much  anxiety  to  parents,  for  they  are  almost  always  thin, 
and,  if  not  diseased,  are  not  healthy.  If  care  be  not  taken,  they  fall  into 
a  scrofulous  condition,  in  which  diseased  joints,  enlarged -glands,  sore 
eyes,  and  even  consumption  occur ;  and  every  effort  should  be  made  to 
overcome  this  dislike.  If  attention  be  given  to  this  matter  of  diet,  there 
need  be  no  anxiety  about  the  possibility  of  increasing  the  quantity  of  food 
consumed ;  whilst  the  neglect,  the  dislike,  will  probably  increase  until 
disease  is  produced.  The  chief  period  of  growth  —  viz.,  from  seven  to 
sixteen  years  of  age  —  is  the  most  important  in  this  respect,  for  a  store  of 
fat  in  the  body  is  then  essential.  Those  who  are  inclined  to  be  fat  usually 
like  fat  in  food,  and  then  it  may  be  desirable  to  limit  its  use.  Some  who 
cannot  eat  it  when  hot  like  it  when  cold,  and  all  should  select  that  kind 
which  they  prefer.  Those  living  in  Russia  and  Lapland  devour  very 
large  quantities  —  as  seven  pounds  daily  —  and  eat  it  even  raw,  while 
those  dwelling  in  hot  countries  use  very  little.  It  produces  more  heat 
than  any  other  kind  of  food."  — Edward  Smith  on  Health. 


21.  Whence  are  fatty  articles  of  food  derived  ? 

22.  Appetite  of  persons  in  cold  climates  ?    What  do  they  require  ?    Upon  what  must 
theyreiy?    Why?    The  Esquimau  ?    Laplander?'  Olive  and  palm  ? 


fHE  CHEMISTRY  OF  FOOJ)  85 

23.  The  Sugars,  or  the  Saccharine  Substances. — These  con- 
stitute the  third  and  last  group  of  the  organic  substances  which 
are  employed  as  food.    This  group  embraces,  in  addition  to  the 
different  kinds  of  Sugar,  the  varieties  of  starch  and  gum,  from 
whatever  source  derived.     The  two  substances  last  named  do 
not,  at  first  sight,  present  many  points  of  similarity  to  sugar ; 
but  they  closely  resemble  it  in  respect  to  their  ultimate  chem- 
ical composition,  being  made  up  of  the  same  elements,  in  nearly 
the  same  proportions.     And  their  office  in  the  system  is  the 
same,  since  they  are  all  changed  into  sugar  by  the  processes  of 
digestion. 

24.  Sugar  is  chiefly  of  vegetable  origin,  the  animal  varieties 
being  obtained  from  honey  and  milk.      The  most  noticeable 
characteristic  of  this  substance  is  its  agreeable,  sweet  taste, 
which  makes  it  everywhere  a  favorite  .article  of  food.      But 
this  quality  of  sweetness  is  not  possessed  by  all  the  varieties 
of  sugar  in  the  same  degree;   that  obtained  from  milk,  for 
instance,  has  a  comparatively  feeble  taste,  but  rather  imparts 
a  gritty  feeling  to  the  tongue.     The  other  important  properties 

9.  The  Effect  of  Climate  on  the  Appetite.  —  "  Climate  has  an  impor- 
tant influence  on  the  quantity  of  food  demanded  by  the  system ;  and 
every  one  has  experienced  in  his  own  person  a  considerable  difference  at 
different  seasons  of  the  year.  Travelers'  accounts  of  the  amount  of  food 
consumed  by  the  natives  of  the  frigid  zone  are  almost  incredible.  They 
speak  of  men  eating  a  hundred  pounds  of  meat  in  a  day ;  and  a  Russian 
admiral,  Saritcheff,  mentions  an  instance  of  a  man  who,  in  his  presence, 
ate  at  a  single  meal  a  mess  of  boiled  rice  and  butter  weighing  twenty- 
eight  pounds.  Although  it  is  difficult  to  regard  these  statements  with 
entire  confidence,  the  general  opinion  is  undoubtedly  well  founded  that 
the  appetite  is  greater  in  cold  than  in  warm  climates.  Dr.  Hayes,  the 
Arctic  explorer,  states,  from  his  own  observation,  that  the  daily  ration  of 
the  Esquimaux  is  from  twelve  to  fifteen  pounds  of  meat,  about  one-third 
of  which  is  fat.  He  once  saw  an  Esquimau  consume  ten  pounds  of  walrus 
flesh  and  blubber  at  a  single  meal,  which  however  lasted  several  hours, 
with  the  thermometer  60°  or  70°  below  zero.  Some  members  of  his  own 
party  manifested  a  constant  craving  for  fatty  substances,  and  were  in  the 
habit  of  drinking  the  contents  of  the  oil-kettle  with  evident  relish."  — 
Flint's  Physiology.  

23.  Which  are  the  third  of  the  organic  groups  ?    What  do  they  embrace  ?    Points  of 
resemblance  ? 

24.  Origin  of  the  sugars  ?    Ordinary  sugar  ?    Beet-root?    Maple-sugar?    Grape-sugar? 
Cane-sugar  ? 


86 


THE  CHEMISTRY  OF  FOOD 


of  sugar  are,  its  power  to  crystallize  when  evaporated  from 
watery  solutions,  such  as  the  juices  of  many  plants;  a  ten- 
dency to  ferment,  by  which  process  alcohol  is  produced ;  and  a 
ready  solubility  in  water.  This  latter  quality  renders  it  Tery 
easy  of  digestion,  and  more  so  than  any  other  of  the  saccharine 
group.  It  is  computed  that  the  annual  production  of  sugar,  in 
all  parts  of  the  world,  is  more  than  one  million  of  tons.  The 
kind  of  sugar  that  is  in  ordinary  use,  in  this  country,  is  pre- 
pared from  the  juice  of  the  sugar-cane,  which  contains  eighteen 
per  cent,  of  sugar.  In  France  it  is  manufactured  from  the 
beet-root,  which  holds  about  nine  per  cent. ;  the  maple-tree  of 
our  climate  yields  a  similar  sugar.  The  sweet  taste  of  fruits 
is  due  to  the  presence  of  grape-sugar:  the  white  grains  seen  on 
raisins  belong  to  this  variety.  Cane-sugar  is  more  soluble  than 
the  latter,  and  has  twice  the  sweetening  power.  (Head  Note  10.) 
25.  Starch.  —  This  is  the  most  widely  distributed  of  the 
vegetable  principles.  It  is  tasteless,  inodorous,  and  does  not 

crystallize.  It  consists  of  mi- 
nute rounded  granules,  which, 
under  the  microscope,  reveal 
a  somewhat  uniform  structure 
(Fig.  21).  Starch  will  not 
dissolve  in  cold  water,  but  in 
boiling  water  the  small  grains' 
burst  open,  and  may  then  be 
dissolved  and  digested. 

26.  The  bread-stuffs- 
wheat,  corn,  and  rye  flours  — 
are  more  than  one-half  starch. 

FIG.    21.  —  GBANULES    OF    POTATO    STARCH   Rice,    which  is    the    "  Staff    of 

life"    to    one-third    of    the 

human  family,  contains  eighty  per  cent.     Unripe  fruits  have 
much  starch  in  them,  which  renders  them  indigestible  when 

10.   Why  too  much  Sugar  is  Injurious.  —  "  Sugar  is  very  wholesome, 
and,  as  I  told  you,  we  want  some  in  our  diet.    But  children  will  often  eat 


25.  Starch,  how  widely  distributed  ?    Its  qualities  ?    Its  constituents  ?    Its  solubility  ? 

26.  How  much  starch  in  bread-stuffs  ?    lu  rice  ?    Unripe  fruits  ?    Bipe  fruits  ? 


THE  CHEMISTRY  OF  FOOD  87 

eaten  uncooked,  for  the  grains  of  raw  starch  are  but  slightly 
acted  upon  within  the  body.  But,  under  the  potent  chemistry 
of  the  sun's  ray,  this  crude  material  is  converted  into  sugar. 
Thus  are  the  fruits  prepared  by  the  careful  hand  of  Nature,  so 
so  that  when  ripe  they  may  be  freely  used  without  further 
preparation. 

27.  Gum  is  commonly  found  in  those  articles  which  also  con- 
tain starch,  and  has  the  same  chemical  composition  as  the 
latter,  but  is  much  less  nutritious.     In  the  East,  gum-arabic 
and  similar  substances  are  largely  employed  as  food.     Persons 
who  travel  by  caravan  across  vast,  sandy  deserts,  find  such 
substances  well  adapted  to  their  wants,  since  they  are  not 
perishable,  and  are  easily  packed  and  carried. 

28.  Stimulating  Substances.  —  The  three  classes  of  food-prin- 
ciples already  considered — the  Albuminoids,  the  Fats,  and  the 
Sugars — comprise  all  the  more  important  organic  ingredients 
of  our  food.     There  are,  besides,  a  great  variety  of  coloring 
and  flavoring  matters,  that  stimulate  or  increase  the  appetite 
for  food  by  appealing  to  the  eye  and  taste ;  but  they  are  not 
nutritious,  and  are  quickly  separated  from  the  truly  useful 
substances,  and  do  not  long  remain  in  the  body.     Among  these 
may  be  classed  spices,  flavors  of  fruits,  tea,  coffee,  and  vege- 
table acids. 


too  much  sugar,  just  as  they  will  eat  too  little  fat.  The  harm  it  does  them 
is — first,  it  is  very  apt  to  spoil  the  teeth ;  second,  it  takes  away  the  ap- 
petite for  other  food.  If  you  are  always  eating  sweet  cakes  and  sugar- 
plums, you  will  not  care  for  plain,  nourishing  diet.  Now,  what  is  best  for 
us  all  is,  to  have  good  appetites  for  wholesome  food  ;  it  will  do  more  to 
keep  us  in  health  all  our  lives  than  anything  else ;  and  there  is  a  great 
deal  in  getting  the  right  habit."  Candies  are  frequently  adulterated  with 
plaster-of-paris,  chalk,  and  certain  forms  of  earth,  that  are  indigestible  ; 
but  worse  than  that,  the  coloring  matters  and  flavoring  extracts  that  are 
used  in  the  bright-tinted  and  fruity-flavored  confectionery  are  absolute 
poisons  in  many  instances,  such  as  arsenic,  copper,  zinc,  lead,  prussic  and 
sulphuric  acid."  —  Berner^s  Lessons  on  Health  (in part}. 


27.  Gum,  where  found  ?    Its  composition  ?    Gum-arabic  f 

28.  The  three  classes  of  food-principles  ?    What  besides?   What  is  said  of  them  ?  Name 
the  articles  not  nutritious. 


88  THE  CHEMISTRY  OF  FOOD 

29.  Necessity  of  a  Regulated  Diet.  —  A  great  variety  of  ex- 
periments have  been  tried,  in  order  to  test  the  relative  value 
of  the  different  nutritive  principles.    They  have  been  practised 
to   some   extent   upon  man,  but  chiefly  upon  those  inferior 
animals  which  require  a  similar  diet  to  man. 

30.  By  this  means  it  has  been  demonstrated  that  —  first, 
when  any  one  of   these  substances  is  eaten  exclusively,  the 
body  is  imperfectly  nourished,  and  life  is  shortened.    Dogs  fed 
exclusively   upon  albumen,  fat,  or  -sugar,   soon  die   of  star- 
vation.     Second,  a  diet   long   deprived  of  any  one  of  these 
principles  is  a  fertile  cause  of  disease ;  for  example,  on  ship- 
board, where  fresh  vegetables  are  not  dealt  out  for  a  long 
period,  scurvy  becomes  prevalent  among  the  sailors.    They  are, 
however,  to  a  certain  extent  mutually  convertible,  and  thus 
the  missing  article  is  indirectly  supplied.     For  instance,  sugar 
changes  to  fat  in  the  body ;  and  hence,  as  is  well  known,  the 
"  hands  "  on  a  sugar  .plantation  grow  fat  during  the  sugar  season 
by  partaking  freely  of  the  ripened  juices  of  the  cane.     (Bead 
Note  11.) 

31.  That  is  the  best  diet,  therefore,  which  contains  some  of 
each  of  these  principles,  in  due  proportion;   and  that  is  the 
worst  which  excludes  the  most  of  them.     The  cravings  and 
experience  of   man  had  unerringly  guided  him  to  a  correct 
regulation  of  his  diet,  long  before  the  chemistry  of  food  was 
understood;    so  that  his  ordinary  meals  long  ago  combined 

11.  The  Effects  of  a  Poor  Diet— "The  food  of  the  poor  in  olden 
times  was  poor  and  scanty  ;  so  much  so,  in  fact,  that  their  pqwers  of  life 
were  depressed  ;  and  we  believe  this  fact  had  much-to  do  with  the  fearful 
mortality  of  the  plague  throughout  Europe  during  the  middle  ages.  The 
lower  classes,  especially  those  living  in  crowded  cities,  and  subsisting  on 
the  scanty  and  monotonous  diet  that  the  historians  of  the  period  describe, 
were  the  principal  sufferers.  From  1296  to  1666,  hundreds  of  thousands 
were  carried  off  by  the  most  fearful  pestilences  the  earth  has  ever  known. 
Rye  in  France  and  oats  in  England  were  for  generations  the  almost  exclu- 
sive diet ;  wheat  was  a  luxury,  which  even  the  rich  might  only  indulge  in 
at  Christmas.  Oats  were  known  in  Germany  2,000  years  ago,  and  were 
probably  the  original  bread-grain  for  all  Europe."  — Dr.  J.  Knight. 


29.  What  is  said  of  experiments  that  have  been  tried  ? 

30.  What  has  been  demonstrated  in  the  first  place  ?    Example  ?    Second  demonstra- 
tion ?    Example  ?    Give  the  illustration  in  relation  to  convertibility. 


THE  CHEMISTRY  OF  FOOD 


89 


these  various  principles,  the  necessity  and  value  of  which  are 
now  explained.     (Head  Notes  12  and  13.) 

12.  Variety  in  Diet  and  in  its   Preparation   Beneficial.  —  "  Every 
dietary  should  contain  fresh  vegetables.     It  is  further  necessary  that  cer- 
tain articles  belonging  to  the  same  class  be  varied  from  day  to  day,  other- 
wise the  appetite  cloys.     Beef  should  alternate  with  mutton,  for  example  ; 
or  variety  should  be  secured  by  different  modes  of  cooking  the  same 
article.     Indeed,  it  is  not  too  much  to  say  that  the  art  of  cookery  is  a 
matter  of  national  importance,  not  only  because  it  renders  food  palatable, 
but  because  the  more  it  is  studied  and  practised  the  greater  is  the 
economy  which «nay  be  effected,     it  is  chiefly  in  this  relation,  that  bever- 
ages, condiments,  etc.,  become  such  valuable  dietetic  adjuncts." — Wil- 
son's Hand-book  of  Hygiene. 

13.  Some    Experiments  as  to  Food.  — "  Magendie  made  numerous 
experiments  on  the  inferior  animals  to  test  the  value  of  different  forms  of 
nutriment.     He  showed  that  a  diet  exclusively  composed  of  starch  and 
sugar  would  not  support  life.     So,  too,  dogs  confined  to  white  bread  and 
water  died  with  all  the  symptoms  of  starvation ;  but  on  the  military 
brown-bread  animals  lived  pretty  well,  as  this  article  contains  a  greater 
variety  of  the  alimentary  principles.     Other  experiments  have  given  an 
account  of  geese  limited  to  some  one  substance.     All  of  them  died  —  the 
animal  fed  upon  gum,  on  the  sixteenth  day ;  that  fed  with  sugar,  on  the 
twenty-first  day  ;  one  fed  with  starch,  on  the  twenty-fourth  day  ;  and  one 
fed  with  white  of  egg,  on  the  twenty-sixth  day.    In  1769,  before  these 
experiments  were  performed,  Dr.  Stark,  a  young  English  physiologist, 
fell  a  victim  at  an  early  age  to  ill-judged  experiments  on  himself  as  to  the 
effects  of  different  foods.     He  lived  for  forty-four  days  on  bread  and 
water,  for  twenty-nine  days  on  bread,  sugar,  and  water,  and  for  twenty- 
four  days  on  bread,  water,  and  olive  oil ;  until  finally,  his  constitution 
became  broken,  and  he  died  from  the  effects  of  his  experiments."  — 
Flint's  Physiology. 

TOPICAL  OUTLINE 


FOODS 


ANIMAL  . 


VEGETABLE 


MINERAL 


Nitrogenous 


Albumen  —  white  of  egg. 
Caseine  —  milk  and  eheese. 
Fibrin  — blood. 
Myosin — muscle. 
Gelatin  —  bone. 


Non-nitrogenous 
f  Nitrogenous  .    . 

I  Non-nitrogenous 


Fats  and  sugar.  _  ^ 

f  Gluten — cereal  grains. 
(  Legumen  —  beans,  etc. 
Stanch  — all  parts  of  plants. 
Sugars  —  all  parts  of  plants. 
Gums  —  all  parts  of  plants. 
Oils— fruits. 
Water,  common  salt,  calcium  carbonate,  calcium 
phosphate,  etc. 


90  THE  CHEMISTRY  'OF  FOOD 


QUESTIONS  FOR  TOPICAL  REVIEW 

PAGE 

1.  What  is  understood  by  the  term  food  ? 75 

2.  What  can  you  state  in  relation  to  the  source  of  food  ? 75 

3.  What  discriminations  and  selections  are  necessary  ? 75 

4.  How  can  you  tell  the  organic  from  the  inorganic  substances? 77 

5.  What  relative  position  does  water  hold  as  an  article  of  food 77 

6.  In  what  parts  of  the  body  is  water  found  ? 77 

7.  In  what  articles  that  we  eat  is  it  found  ? 78 

8.  If  you  were  required  to  go  without  water  or  solid  food  for  a  number 

of  days,  which  would  you  prefer  to  have,  and  why  ? 78 

9.  What  can  you  state  of  the  importance  of  salt  as  an  article  of  food  ?.  78,  79 

10.  How  abundant  is  salt,  and  how  does  it  find  its  way  into  the  human 

system  ? 78,  79,  80 

11.  What  can  you  state  of  the  importance  of  lime  in  the  body?    In 

what  does  it  occur  ? 80,  81 

12.  What,  of  the  importance  of  iron  ? 81 

13.  What  further  is  stated  of  other  inorganic  substances  ? 81 

14.  What  in  relation  to  organic  substances  ? 81,  82 

15.  What  can  you  state  in  relation  to  the  albuminoids  ? 82 

1(5.  What,  in  relation  to  albumen  ? 82 

17.  What,  in  relation  to  caseine  ? 83 

18.  In  relation  to  the  fats  or  oils,  and  how  generally  consumed  ? 83,  84 

19.  What  do  we  understand  by  the  sugars  or  saccharine  substances?. . .        85 

20.  State  what  you  can  of  sugar  — its  origin  and  various  qualities 85,  86 

21.  Of  starch  — its  varieties  and  qualities 86 

22.  Of  the  abundance  of  starch,  and  its  importance  as  a  food-principle.  86,  87 

23.  What  is  stated  in  relation  to  stimulating  substances  ? 87 

24.  Of  the  necessity  for  regulation  in  diet  ? 88 

25.  What  is  considered  the  most  healthful  diet  ? 88,  89 


CHAPTER  V 

FOOD  AND  DRINK 

•» 

Necessity  for  Food  —  Waste  and  Repair  —  Hunger  and  Thirst  —  Amount 
of  Food  —  Renovation  of  the  Body  —  Mixed  Diet  —  Milk  —  Eggs  — 
Meat  —  Cooking  —  Vegetable  Food — Bread — The  Potato  —  Fruits  — 
Purity  of  Water  —  Action  of  Water  upon  Lead — Coffee,  Tea,  and 
Chocolate  —  Effects  of  Alcohol 

1.  Necessity  for  Food. — Activity  is  everywhere  followed  by 
waste.     The  engine  uses  up  coal  and  water  to  produce  motion, 
the  stream  wears  away  its  bank,  the  growing  corn-blade  draws 
tribute  from  the  soil.     When  the  human  body  acts,  and  it  is 
always  in  action  during  life,  some  of  its  particles  are  worn  out 
and  thrown  off.     This  waste  must  constantly  be  repaired,  or 
the  body  suffers.     In  this  fact  is  seen  the  necessity  for  food. 
The   particles,  thus  worn  out,  being  henceforth  useless,  are 
removed  from  the  body.     Our  food  and   drink   are   rapidly 
transformed  into  a  new  supply  of  living,  useful  material,  to 
be  in  turn  used  up  and  replaced  by  a  fresher  supply. 

2.  Waste   and  Repair. — In  this   way  the   healthful  body, 
though  always  wasting,  is  always  building  up,  and  does  not 
greatly  change  in  size,  form,  or  weight.     At  two  periods  of 
life  the  processes  of  waste  and  repair  are  not  exactly  balanced. 
In  early  life  the  process  of  building  up  is  more  active,  and  in 
consequence  the   form   is   plump   and  the   stature  increases. 
Repair  now  exceeds  waste.     On  the  other  hand,  when  old 
age  comes  on,  the  wasting  process  is  more  active,  the  flesh 
and  weight  diminish,  the  skin  falls  in  wrinkles,  and  the  senses 
become  dull.     Only  during  the  prime  of  life  —  from  about 

1.  What  follows  activity  ?    Examples  ?    Necessity  for  food? 

2.  Give  the  theory  in  relation  to  waste  and  repair. 

91 


92  FOOD  AND  DRINK 

twenty  to  sixty  years  of  age  —  is  the  balance  exact  between 
loss  and  gain.     (Read  Note  1.) 

3.  Hunger  and  Thirst.  —  When  the  system  is  deprived  of  its 
supply  of  solid  food  during  a  longer  time  than  usual,  nature 
gives  warning  by  the  sensation  of  hunger,  to  repair  the  losses 
that  have  taken  place.     This  sensation  or  pain  appears  to  be 
located  in  the  stomach,  but  it  is  really  a  distress  of  the  system 
at  large.     Let  a  sufficient  quantity  of  nourishment  be  intro- 
duced into  the  system  in  any  other  way  than  by  the  mouth, 
and  it  will  appease  hunger  just  as  certainly  as  when  taken  in 
the  usual  manner. 

4.  The  feeling  of  thirst,  in  like  manner,  is  evidence  that 
the  system  is  suffering  from  the  want  of  water.     The  apparent 
seat  of  the  distress  of  thirst  is  in  the  throat;  but  the  injection 
of  water  into  the  blood-vessels  is  found  to  quench  thirst,  and 
by  the  immersion  of  the  body  in  water,  the  skin  will  absorb 
sufficient  to  satisfy  the  demands  of  the  system.     The  length 
of  time  that  man  can  exist  without  food  or  drink  is  estimated 
to  be  about  seven  days.     If  water  alone  be  supplied,  life  will 

1.  The  Waste  of  the  Body.  —  "In  the  physical  life  of  man  there  is 
scarcely  such  a  thing  as  rest  —  the  numberless  organs  and  tissues  which 
compose  his  frame  are  undergoing  perpetual  change,  and  in  the  exercise 
of  the  function  of  each  some  part  of  it  is  destroyed.  Thus,  we  cannot 
think,  feel  or  move  without  wasting  some  proportion,  great  or  small, 
according  to  the  energy  of  the  act,  of  the  apparatuses  concerned  —  such 
as  brain,  nerve  or  muscles.  Now  this  waste-product  cannot  remain  in 
its  original  situation,  where  it  would  not  only  be  useless  dross,  but  also 
obstructive  and  injurious.  Such  old  material  is  being  daily  removed 
from  our  bodies  to  the  average  amount  of  three  or  more  pounds;  and 
that  an  equal  quantity  of  new  shall  take  its  place  is  the  first  principle  of 
alimentation.  To  express  it  in  commercial  language,  the  income  must  be 
equal  to  the  expenditure  ;  and  in  each  of  us  the  amount  of  this  exchange 
must  in  a  lifetime  reach  many  tons.  This  tissue-change  is  so  complete, 
that  not  a  particle  of  our  present  body  will  be  ours  a  short  time  hence  ; 
and  we  will  be,  as  I  have  lately  seen  it  phrased,  like  the  knife  which, 
after  having  had  several  new  blades,  and  at  least  one  new  handle,  was 
still  the  same  old  knife  to  its  owner.  We  are,  in  fact,  constantly  *  moult- 
ing.1 "  — Mapother's  Lectures  on  Public  Health. 


8.  System  deprived  of  food  ?    Warning  ?    What  is  the  pain  ?    How  proved  ? 
4.  Feeling  of  thirst  ?    Seat  of  the  pain  ?    How  proved  ?    Time  a  person  can  exist  with- 
out food  ? 


FOOD  AND  DRINK  93 

last  much  longer  —  there  being  cases  recorded  where  men  have 
lived  twenty  days  and  over  without  taking  any  solid  food. 
(Bead  Note  2.) 

5.  Quantity  of  Food.  — The  quantity  of  food  required  varies 
greatly,  according  to  the  individual  and  his  mode  of  life.     The 
young,  and  others  who  lead  active  lives,  or  who  live  in  the  open 
air,  require  more  food  than  the  old,  the  inactive,  or  the  sed- 
entary.    Those  who  live  in  cold  regions  require  more  than  - 
the  inhabitants  of  hot  climates.     Habit,  also,  has  much  to  do 
with  the  quantity  of  food  required.     Some  habitually  eat  and 
drink  more  than  they  actually  need,  while  a  few  eat  less  than 
they  should. 

6.  The   average  daily  quantity  of   food  and  drink  for  a 
healthy  man  of  active  habits  is  estimated  at  six  pounds.     This 
amount  may  be  divided  in  about  the  following  proportions : 
the  mineral  kingdom  furnishes  three  and  one-half  pounds,  in- 
cluding water  and  salt ;  the  vegetable  kingdom,  one  and  one- 
half  pounds,   including  bread,   vegetables,    and   fruits;    the 
animal  kingdom,  one  pound,  comprising  meat,  eggs,  butter,  and 
the  like.     This  quantity  is  about  one  twenty-fourth  the  weight 

2.  Hunger  and  Thirst.  —  "  We  none  of  us  object  to  a  sharp-set  appe- 
tite ;  that  is 'by  no  means  unpleasant,  especially  when  there  is  food  at 
hand  ;  but  if  this  is  not  the  case,  it  soon  becomes  a  craving  passion — a 
strong  impelling  power.  The  cravings  of  hunger  have  done  much  for  this 
world;  'look  where  we^may,  we  see  it  as  the  motive  power  which  sets 
the  vast  array  of  human  machinery  in  action. '  Hunger  is  also  the  incen- 
tive which  directs  our  attention  to  the  system's  need  for  food,  and  if  it 
be  sharp  enough  the  most  loathsome  substances  are  greedily  devoured. 
By  it  has  man,  and  civilized  man,  too,  been  driven  to  feed  upon  the 
putrid  corpse  of  his  comrade.  Hunger  is  one  of  the  great  forces  in  action 
in  the  preservation  of  the  life  of  the  individual ;  and  the  fear  of  it  is  one 
of  the  strongest  incentives  to  action.  But  the  pangs  of  hunger  are  toler- 
able in  comparison  with  the  tortures  of  raging  thirst.  In  fact,  so  terrible 
are  the  latter  that  they  form  one  of  the  cruelest  tortures  which  man  can 
inflict  on -man;  so  cruel  a  torture,  indeed,  that  it  has  rarely  been  used, 
except  in  cases  of  bitter  personal  animosity,  by  others  than  brutal  Eastern 
tyrants,  or  bigots  under  the  influence  of  religious  fanaticism."  —  Fother- 
gill  on  the  Maintenance  of  Health. 


5.  Amount  of  food  required  ?    The  young  and  others  ?    Those  living  in  hot  and  cold 
climates?    Habits? 

fi.  Quantity  of  food  daily  ?    How  divided  ?    Compare  with  the  weight  of  the  body.  _ 


94 


FOOL  AND  DRINK 


of  the  body,  as  it  is  generally  computed ;  the  average  weight 
of  an  adult  man  being  placed  at  140  pounds.  A  man,  there- 
fore, consumes  an  amount  of  solid  and  liquid  nutriment  every 
twenty-four  days  equal  in  weight  to  that  of  his  body,  a  corre- 
sponding amount  being  excreted,  or 'removed  from  the  system  in 
the  same  time.  (Bead  Notes  3  and  4). 

3.  A  Lifetime  Allowance  of  Food.  —  "M.   Soyer,   in  his  'Modern 
Housewife,'  makes  a  calculation  as  to  how  much  food  an  epicure  of  70 
years  of  age  has  consumed.    This  imaginary  epicure,  who  is  supposed  to 
be  a  wealthy  personage,  is  placed  by  him  on  Primrose  Hill  at  ten  years 
old  and  told  to  look  around  him  at  the  vast  assemblage  of  animals  and 
other  objects  he  will  in  the  course  of  a  lifetime  send  down  his  throat  — 
the  sight  of  which  is,  of  course,  described  as  appalling.    Among  the  other 
things,  he  is  to  devour  30  oxen,  200  sheep,  100  calves,  200  lambs,  50  pigs, 
1,200  fowls,  300  turkeys,  263  pigeons,  120  turbot,  140  salmon,  30,000 
oysters,  5,745  Ibs.  of  vegetables,  243J  Ibs.  of  butter,  24,000  eggs,  and4| 
tons  of  bread,  besides  fruits,  sweetmeats,  etc.,  and  49  hogsheads  of  wine, 
548  gals,  of  spirits,  and  about  3,000  gals,  of  tea  and  coffee.     This  is  a 
mere  outline  of  what  we  are  told  is  c\stined  to  be  consumed.     To  show 
there  is  no  exaggeration,  Soyer  assures  us  that  he  has  from  experience 
made  up  a  scale  of  food  for  the  day  for  a  period  of  60  years,  and  it 
amounts  to  33|  tons  of  meat,  farinaceous  food,  and  vegetables,  etc." — 
Journal  of  Chemistry. 

4.  A  Daily  Ration  for  an  Adult  Man.  — "We  may  arrive  at  something 
like  an  average  daily  diet  by  taking  the  case  of  the  man  in  good  health, 
weighing  154  Ibs.,  and  measuring  5  feet  8  inches  in  height.     Simply  to 
maintain  his  body,  without  loss  or  gain  in  weight,  his  ration  of  food 
should  not  contain  less,  during  24  hours,  than  the  following  proportions 
and  quantities  of  the  main  ingredients  :* 

THE  AVERAGE  DAILY  DIET  FOR  AN  ADULT 


FOOD   SUBSTANCES. 

PER  CENTUM. 

WEIGHT. 

"Water                                 

81.5 

Ibs.       oz. 
5          8 

grs. 
320 

3  9 

4 

110 

Starch,  sugar,  etc.    .     .    ._   
Fat                                      "        

10.6 
3.0 

11 
3 

178 
337 

7 

825 

Phosphates  potash  salts  etc        

.3 

- 

170 

100. 

6        13 

128 

"  Water,  it  will  be  remembered,  enters  into  the  composition  of  every 
article  of  food  as  well  as  in  the  liquids  we  drink.     In  reality,  the  weight 


FOOD  AND  DRINK  95 

7.  Renovation   of  the-  Body.  —  By  this   process,  so  far   as 
weight  is  concerned,  the  body  might  be  renewed  every  twenty- 
four  days ;  but  these  pounds  of  food  are  not  all  real  nutriment. 
A  considerable  portion  of  that  which  we  eat  is  innutritions, 
and  though  useful  in  various  ways,  is  not  destined  to  repair 
the  losses  of  the  system.     An  opinion  has  prevailed  that  the 
body  is  renewed  throughout  once  in  seven  years ;  how  correct 
this  may  be,  it  is  not  easy  to  decide,  but  probably  the  reno- 
vation of  the  body  takes  place  in  a  much  shorter  period. 
Some  parts  are  very  frequently  renewed,  the  nutritive  fluids 
changing  more  or  less  completely  several  times  during  the  day. 
The   muscles,  and  other   parts  in  frequent  exercise,  change 
often  during  a  year;  the  bones  not  so  often,  and  the  enamel 
of  the  teeth  probably  never  changes  after  being  once  fully 
formed.     (Read  Note  5.) 

8.  Mixed  Diet. — The  habits  of  different  nations  in  respect 
to  diet  exhibit  the  widest  and  strangest  diversity.     The  civil- 
ized cook  their  food,  while  savages  often  eat  it  in  a  raw  state. 
Some  prefer  it  when  fresh ;  others  allow  it  to  remain  until  it 
has  become  tainted  with  decay.     Those  dwelling  in  the  far 

of  the  dry  food  we  take  will  exceed  that  given  above ;  chiefly  for  the 
reason  that  they  do  not  come  to  us  pure  and  unmixed  with  fibrous 
material  and  gelatine,  whose  use  in  nourishing  the  body  is  limited  and 
uncertain."  —  Kensington  Museum  Hand-Book  on  Food. 

5.  The  Renewal  of  the  Body.  —  "To  meet  these  constant  chemical 
changes,  material  is  taken  in,  in  the  form  of  food  and  drink,  Which  is 
being  constantly  assimilated,  and  so  nutrition  and  repair  are  conducted. 
The  rapidity  with  which  these  changes  are  carried  on  is  much  greater 
than  is  usually  supposed.  Paley,  in  his  'Natural  Theology,'  states  that 
seven  years  are  requisite  for  the  perfect  renewal  of  the  body ;  and  this 
statement,  owing  partly  to  the  mysticism  associated  with  the  number  7, 
is  generally  accepted  and  believed.  The  time  really  is  rather  months 
than  years  ;  but  it  is  absurd  to  fix  a  time  which  must  necessarily  vary  in 
different  individuals,  being  much  less  in  the  infant  than  in  the  aged,  in 
the  active  than  the  indolent;  widely  different,  too,  in  various  tissues, 
from  the  epithelium  lining  of  the  glands  of  the  stomach,  renewed  several 
times  in  each  act  of  digestion,  to  the  enamel  of  the  tooth,  which  is  proba- 
bly never  renewed  during  a  lifetime." 


7.  How  often,  then,  might  the  body  be  renewed  ?    Why  is  it  not  ?    Opinion  ?    How 
correct  ?    What  further  is  stated  ? 

8.  Habits  of  nations  ?    Give  the  different  cases. 


96  FOOD  AND  DRINK 

north  subsist  almost  wholly  on  animal  food,  while  those  living 
in  hot  climates  have  bountiful  supplies  of  delicious  fruits  with 
which  to  satisfy  all  their  bodily  wants.  One  race  subsists 
upon  the  banana,  another  upon  the  blubber  of  seals.  In 
temperate  climates,  a  diet  composed  partly  of  vegetable  and 
partly  of  animal  food  is  preferred.  (Bead  Note  6.) 

9.  The  important  point  to  consider  is,  however,  not  one  of 
origin,  but  whether  the  chemical  principles  (mentioned  in  the 
last  chapter)  enter  into  the  composition  of  the  diet.     A  purely 
vegetable  diet  may  be  selected  which  would  contain  all  the 
principles  necessary  to  sustain  life.     It  is  recorded  of  Louis 
Cornaro,  a  Venetian  noble,  that  he  supported  himself  comfort- 
ably for  fifty-eight  years  on  a  daily  allowance  of  twelve  ounces 
of  vegetable  food,  and  about  a  pint  of  light  wine.     On  the 
other  hand,   the   food   of    John    the    Baptist,   consisting    of 
"locusts  and  wild  honey,"  is  an  example  of  the  sustaining 
power  of  a  diet  chiefly  animal  in  its  origin. 

10.  In  our  climate,  those  who  lead  active  lives  crave  an 
allowance  of  animal  food ;  and  it  has  been  found  by  experience 
that  with  it  they  can  accomplish  more  work  and  are  less  sub- 
ject to  fatigue,  than  without  it.     Among  nations  where  an 
exclusively  vegetable  diet  is  employed,  indigestion  is  a  dis- 
order especially  prevalent.     (Read  Note  7.) 

6.  Different  Effects  of  Animal  and  Vegetable  Food.  —  "Raw  meat 
gives  fierceness  to  animals,  and  would  do  the  same  to  man.     This  is  so 
true  that  the  English,  who  eat  their  meat  underdone,  seem  to  partake  of 
this  fierceness  more  or  less,  as  shown  in  pride,  hatred,  and  contempt  of 
other  nations."  —  De.La  Mettrie. 

"The  carnivora  are,  in  general,  stronger,  bolder,  and  more  pugnacious 
than  the  herbivora  on  which  they  prey  ;  in  like  manner,  those  nations 
who  live  on  vegetable  food  differ  in  disposition  from  such  as  live  on 
flesh."  —  Liebig. 

7.  A  Mixed  Diet  affords  the  Best  Results.  — "  The  mixed  diet  to 
which  the  inclination  of  man  in  temperate  climates  seems  usually  to  lead 
him,  when  circumstances  allow  that  inclination  to  develop  itself  freely, 
appears  to  be  fully  conformable  to  the  construction  of  his  dental  and 
digestive  apparatus,  as  well  as  to  his  instinctive  cravings.    And  whilst 


9.  The  point  to  consider  ?    Vegetable  diet  ?    Louis  Cornaro  ?    John  the  Baptist  ? 
10.  What  has  been  found  in  our  climate  ?    Exclusive  vegetable  diet  ? 


FOOD  AND  DRINK  97 

11.  The  necessity  for  occasionally  changing  or  varying  the 
diet,  is  seen  in  the  fact  that  no  single  article  comprises  all  the 
necessary  principles  of  food,  and  that  the  continuous  use  of 
any  one  diet,  whether  salt  or  fresh,  is  followed  by  defective 
nutrition  and  disease.     There  is  one  exception  to  this  rule :  in 
infancy,  milk  alone  is  best  calculated  to  support  life ;  for  then 
the  digestive  powers  are  incompletely  developed,  and  the  food 
must  be  presented  in  the  simplest  form  possible.     It  should 
also  be  remembered  that  too  rich  diet  is  injurious,  just  as  truly 
as  one  that  is  inadequate.  »When  the  food  of  horses  is  too 
nutritious,  instinct  leads  them  to  gnaw  the  wood-work  of  their 
mangers. 

12.  Different  Articles  of  Diet  —  Milk. — Milk  is  the  earliest 
nutriment  of  the  human  race,  and  in  the  selection  and  arrange- 
ment of  its  constituents,  may  be  regarded  as  a  model  food,  no 
other  single  article  being  capable  of  sustaining  life  so  long. 
Cow's  milk  holds  caseine,  one  of  the  albuminoids,  about  five 
parts  in  one  hundred ;  a  fatty  principle,  when  separated,  known 
as  butter,  about  four  parts ;  sugar  of  milk  four  parts ;  water 
and  salts  eighty-seven  parts.     The  caseine  and  fatty  substance 
are  far  more  digestible  in  milk  than  after  they  have  been  sepa- 
rated from  it  in  the  form,  of  cheese  and  butter. 

13.  Since  milk,  in  itself,  is  so  rich  an  article  of  food,  the 
use  of  it  as  a  beverage  is  unwise,  unless  the  quantity  of  the 

on  the  one  hand  it  may  be  freely  conceded  to  the  advocates  of  '  vegeta- 
rianism,' that  a  well-selected  vegetable  diet  is  capable  of  producing,  in 
the  greatest  number  of  individuals,  the  highest  physical  development  of 
which  they  are  capable,  it  may,  on  the  other  hand,  be  affirmed  with 
equal  certainty,  that  the  substitution  of  a  moderate  proportion  of  animal 
flesh  is  in  no  way  injurious ;  but,  so  far  as  our  evidence  at  present 
extends,  this  seems  rather  to  favor  the  highest  mental  development. 
And  we  can  scarcely  avoid  the  conclusion  that  the  Creator,  by  conferring 
on  a  man  a  remarkable  range  of  choice,  intended  to  qualify  him  for  sub- 
sisting on  those  articles  of  diet,  whether  animal  or  vegetable,  which  he 
finds  most  suitable  to  his  tastes  and  wants." — W.  B.  Carpenter  on  the 
Principles  of  Physiology. 


11.  Necessity  for  change  In  diet  ?  Continuous  use  of  the  same  diet  ?  Exception  ?  Why  ? 
Too  rich  diet  ?    Horses  ? 

12.  Milk  as  a  model  food  ?    Cow's  milk  ?    The  constituents  when  separated  ? 
18.  Milk  as  a  beverage  ?    Milk  sold  in  cities  ?    How  to  detect  the  cheat  ? 


98  FOOD  AND  DRINK 

other  articles  consumed  be  reduced  at  the  same  time.  The 
milk  sold  in  cities  is  apt  to  be  diluted  with  water.  The  way 
to  detect  the  cheat  is  by  testing  the  specific  gravity  of  the 
article.  Good  milk  is  about  1030 ;  skimmed  milk,  1035 ;  but 
milk  diluted  one-fifth  is  1024.  An  instrument  called  the 
lactometer  is  also  used,  by  which  the  amount  of  cream  present 
is  ascertained. 

14.  Eggs. — The  egg  is  about  two-thirds  water,  the  rest  is 
pure  albumen  and  fat  in  nearly  equal  portions.     The  fat  is  in 
the  yolk,  and  gives  it  its  yellow  color.     Eggs  contain  none  of 
the  sugar  principles,  and  should  be  eaten  with  bread  or  vege- 
tables that  contain  them.    Soft-boiled  eggs  are  more  wholesome 
than  those  which  are  hard-boiled  or  fried,  as  the  latter  require 
longer  time  to  digest. 

15.  Meats.  —  The  meats,  so  called,  are   derived   from  the 
muscular  parts  of  various  animals.     They  are  most  important 
articles  of  food  for  adults,  inasmuch  as  they  are  richly  stored 
with  albuminoid  substances  and  contain  more  or  less  fat.    Such 
food  is  very  nourishing,  and   easily  digested  if  eaten  when 
fresh, — veal  and  pork  being  exceptions.     The  flesh  of  young 
animals  is  more  tender  and,  in  general,  more  digestible  than 
that  of  older  ones.     All  meat  is  more  tough  immediately  after 
the  killing  of  the  animal,  but  improves  by  being  kept  a  certain 
length  of  time. 

16.  Some  persons  prefer  flesh  that  has  begun  to  show  signs 
of  decomposition,  or  is  unmistakably  putrid.    By  some,  venison 
is  not  considered  to  have  its  proper  flavor  until  it  is  tainted. 
In  England,  people  prefer  mutton  that  is  in  a  similar  condition, 
just  as  on  the  continent  of  Europe  many  delight  in  cheese  that 
is  in  a  state  of  decomposition.     In  certain  less  civilized  coun- 
tries, flesh  is  not  only  eaten  uncooked,  but  in  a  mouldy,  rotten 
condition.     The  use  of  such  food  is  not  always  immediately 
injurious,  but  it  predisposes  to  certain  diseases,  as  indigestion 
and  fevers.     (Read  Note  8.) 


14.  Composition  of  eggs  ?    Yolk  ?    How  should  eggs  be  eaten  ?    Why  ?    How  boiled  ? 
Why? 

15.  Meats,  whence  derived  ?    Why  important  ?    Flesh  of  young  animals  ? 

16.  Preference  of  persons?    Venison?    Mutton?    Cheese?    Uncooked  flesh  J 


FOOD  AND  DRINK  99 

17.  Cold  is  one  means  of  preserving  meat  from  decay.     In 
the  markets  of  northern  Russia,  the  frozen  carcasses  of  animals 
stand  exposed  for  sale  in  the  winter  air  for  a  considerable  time, 
and  are  sawed  in  pieces,  like  sticks  of  wood,  as  the  purchases 
are  made  —  such  meat,  when  thawed,  being  entirely  fit  for 
food.     Beef  and  pork  are  preserved  by  salting  down  in  brine, 
and  in  this  condition  may  be  carried  on  long  voyages,  or  kept 
for  future  use.     Salted  meat  is  not  as  nutritious  as  fresh,  since 
the  brine  absorbs  its  rich  juices  and  hardens  its  fibres.     Long- 
continued  use  of  salt  meats,  without  fresh  vegetables,  gives 
rise  to  the  disease  called  scurvy,  formerly  very  prevalent  on 
ship-board  and  in  prisons,  but  now  scarcely  known. 

18.  Cooking.  —  The  preparation  of  food  by  the  agency  of  fire 
is  of  almost  universal  practice,  even  among  the  rudest  nations. 
The  object  of  cooking  is  to  render  food  more  easy  of  digestion 
by  softening  it,  to  develop  its  flavor,  and  to  raise  its  tempera- 
ture more  nearly  to  that  of  the  body.     A  few  articles  of  flesh- 
food  are  eaten  uncooked  in  civilized  lands,  the  oyster  being 
an  instance.     Eaw  meat  is  occasionally   eaten  by  invalids 
with  weak  digestive  powers,  and  by  men  training  for  athletic 
contests.     - 

19.  The  cooking  may  be  so  conducted  as  to  rob  the  meat  of 
its  tenderness,  and  of  its  flavor.     The  proper  method,  in  order 

8.  A  Summary  Concerning  Diet.  —  "  The  food  on  which  the  man  who 
would  be  healthy  should  live,  should  be  selected  so  as  to  insure  a  variety 
without  excess.  Animal  food  should  not  be  taken  oftener  than  twice 
daily.  The  amount  of  animal  and  vegetable  food  combined  should  not 
exceed  30  ounces  in  the  24  hours ;  and  for  the  majority  of  persons  an 
average  of  24  ounces  of  mixed  solid  food,  a  third  only  of  which  should  be 
animal,  is  sufficient.  All  animal  foods  should  be  eaten  while  they  are 
fresh,  and  after  they  been  have  well  cooked.  The  habit  of  eating  under- 
done flesh  is  an  almost  certain  cause  of  parasitic  disease.  The  amount  of 
fluid  taken,  in  any  form,  should  not  exceed  the  average  of  24  ounces 
daily.  Water  is  the  only  natural  beverage."  —  Dr.  B.  W.  Bichardson, 
The  Diseases  of  Modern  Life. 


17.  Cold  as  a  preserver  ?    Meat  i«  Russia  ?    Beef  and  pork,  how  preserved  ?    Salted 
meat  as  food  ?    Scurvy  ? 

18.  The  antiquity  of  the  custom  of  cooking  food  ?    Object  of  cooking  ?    The  oyster  ? 
Raw  meat  as  an  occasional  food  ? 

19.  Effect  of  boiling  meat?    How  may  the  cooking  be  done?    The  proper  method? 
Effect?    Making  of  soup  ? 


100  FOOD  AND  DRINK 

to  preserve  or  promote  these  qualities,  is  to  place  the  meat  in 
boiling  water,  which,  after  a  few  minutes,  should  be  reduced 
in  temperature.  In.  this  way  the  intense  heat,  at  first,  coagu- 
lates the  exterior  layers  of  albumen,  and  imprisons  the  delicate 
juices;  after  that,  moderate  heat  best  softens  it  throughout. 
When  soup  is  to  be  made  an  opposite  course  should  be  pursued; 
for  then  the  object  is  to  extract  the  juices  and  reject  the  fibre. 
Meat,  for  such  purpose,  should  be  cut  in  small  pieces  and  piit 
into  cold  water,  which  should  then  be  gradually  raised  to  boil- 
ing heat.  (Bead  Note  9.) 

20.  Boasting  is  probably  the  best  method  of  cooking  meat, 
especially  "joints"  or  large  pieces,  as  by  this  process  the  meat 
is  cooked  in  its  own  juices.  Boasting  should  begin  with  intense 
heat,  and  be  continued  at  a  moderate  temperature,  in  order 
to  prevent  the  drying  out  of  the  nutritious  juices,  as  by  this 
process  an  outer  coating  or  crust  of  coagulated  albumen  is 
formed.  During  this  process  the  meat  loses  one-fourth  of  its 

9.  Cooking  Paves  the  Way  for  Easy  Digestion. — The  objects  to  be 
obtained  by  cooking  meat  are :  1.  To  coagulate  the  albumen  and  blood 
of  the  tissues,  so  as  to  render  the  meat  agreeable  to  the  sight.  2.  To 
develop  flavors,  and  to  make  the  tissue  crisp,  as  well  as  tender,  and  there- 
fore more  easy  of  mastication  and  digestion.  3.  To  secure  a  certain 
temperature,  and  thus  to  be  a  means  of  conveying  warmth  to  the  system. 
4.  To  kill  parasites  in  the  tissues  of  the  meat. 

The  action  of  heat  should  not  be  continued  after  these  objects  are 
accomplished,  as  the  meat  will  thereby  be  rendered  indigestible.  If  a 
piece  of  meat  be  placed  in  water  which  is  briskly  boiling,  a  crust,  so  to 
speak,  is  formed  by  the  rapid  coagulation  of  the  albumen  upon  and  near 
the  surface ;  so  that  the  juice  of  the  meat  cannot  escape,  nor  the  water 
penetrate  its  interior.  If,  on  the  other  hand,  the  meat  be  put  in  cold 
water,  and  slowly  heated,  the  meat  is  left  poor  and  tasteless.  Even  in 
roasting  meat  the  heat  must  be  strongest  at  first,  and  it  may  then  be 
much  reduced.  The  juice  which,  as  in  boiling,  flows  out,  evaporates,  in 
careful  roasting,  from  the  surface  of  the  meat,  and  gives  to  it  the  dark 
brown  color,  the  lustre,  and  the  strong  aromatic  taste  of  roast  meat.  All 
baked  and  roasted  fatty  foods  are  apt  to  disagree  with  delicate  stomachs : 
and  it  is  often  remarked  that,  although  bread  and  butter,  boiled  puddings, 
boiled  fish,  or  boiled  poultry  can  be  eaten  freely  without  discomfort,  yet 
toast  and  butter,  or  meat  pies  and  pastry,  or  fried  fish,  or  roasted  fow) 
will  disagree  with  the  stomach.  —  Letheby  on  Food. 


20.  Boasting  ?    How  should  it  be  done  ?    Give  the  philosophy  of  the  process.    Frying  ? 


FOOD  AND  DRINK  101 

weight,  but  the  loss  is  almost  wholly  water,  evaporated  by  the 
heat.  Too  intense  or  prolonged  heat  will  dry  the  meat,  or 
burn  it.  Frying  is  the  worst  possible  method,  as  the  heated 
fat,  by  penetrating  the  meat,  or  other  article  placed  in  it,  dries 
and  hardens  it,  and  thus  renders  it  indigestible. 

21.  Trichina.  —  It  should  be  remembered  that  ham,  sausages, 
and  other  forms  of  pork  should  never  be  eaten  in  a  raw  or 
imperfectly  cooked  condition.     The  muscle  of  the  pig  is  often 
infested  by  a  minute  animal  parasite,  or  worm,  called  trichina 
spimlis.     This  worm  may  be  introduced  alive,  in  pork  food, 
into  the  human  body,  where  it  multiplies  with  great  rapidity, 
and  gives  rise  to  a  painful. and  serious  disease.     This  disease 
has  been  prevalent  in  Germany,  and  cases  of  it  occur  from 
time  to  time  in  this  country. 

22.  Fish.  —  The  part  of  fish  that  is  eaten  is  the  muscle,  just 
as  in  the  case  of  the  meats  and  poultry.     It  closely  resembles 
flesh  in  its  composition,  but  is  more  watery.    Some  varieties  are 
very  easy  of  digestion,  such  as  salmon,  trout,  and  cod ;  others 
are  quite  indigestible,  especially  lobsters,  clams,  and  shell-fish 
generally.     A  diet  in  which  fish  enters  as  the  chief  article,  is 
ill  adapted  to  strengthen  mind  or  body,  while  its  continued 
use  is  said  to  be  the  fertile  source  of  nearly  every  form  of 
disease  of  the  skin.    Some  persons  are  so  constituted  that  they 
can  eat  no  kind  of  fish  without  experiencing  unpleasant  results. 

23.  Vegetable  Food.  —  The  list  of  vegetable  articles  of  diet 
is  a  very  long  one,  including  the  grains  from  which  our  bread- 
stuffs  are  made,  the  vegetables  from  the  garden,  and  the  fruits. 
All  the  products  of  the  vegetable  kingdom  are  not  alike  useful. 
Some  are  positively  hurtful ;  indeed  the  most  virulent  poisons, 
as  strychnia  and  prussic  acid,  are  obtained  from  certain  vege- 
tables.    Again,  of  such  articles  as  have  been  found  good  for 
food,  some  are  more  nourishing  than  others ;  some  require  very 
little  preparation  for  use,  while  others  are  hard  and  indigest- 


21 .  What  is  "  Trichina  ?  "    How  guarded  against  ? 

22.  What  part  of  fish  is  eaten  ?    What  does  it  resemble  ?    Fish  as  food  for  digestion  ? 
Fish  as  a  diet? 

23.  List  of  vegetable  articles?    Usefulness  of  the  different  vegetables?    Strychnia? 
What  further  is  said  in  relation  to  the  nourishing  and  other  qualities  of  vegetables  ? 


102  FOOD  AND  DRINK 

ible,  and  can  only  be  used  after  undergoing  many  preparatory 
processes.  Great  care  must  therefore  be  exercised,  and  many 
experiments  made,  before  we  can  arrive  at  a  complete  knowl- 
edge in  reference  to  these  articles  of  diet.  Tea,  coffee,  and 
other  substances  from  which  drinks  are  made  are  of  vegetable 
origin. 

24.  Bread.  — Wheat  is  the  principal  and  most  valuable  kind 
of  grain  for  the  service  of  man.     Bread  made  from  wheat-flour 
has   been  in  use  for  many  hundreds  of  years,  and  on  this 
account,  as  well  as  because  of  its  highly  nourishing  properties, 
has  been  aptly  called  "  the  staff  of  life."     We  never  become 
tired  of  good  bread  as  an  article  of  daily  food.     The  white 
kinds  of  flour  contain  more  starch  and  less  gluten  than  the 
darker,  and  are  therefore  less  nutritious.    The  hard-grain  wheat 
yields  the  best  flour.     In  grinding  wheat,  the  chaff  or  bran  is 
separated  by  a  process  called  "bolting."     Unbolted  flour  is 
used  for  making  brown  or  Graham  bread.     (Read  Note  10.) 

25.  The  form  of  bread  most  easily  digested  is  that  which 
has  been  "leavened,"  or  rendered  porous  by  the  use  of  yeast, 
or  by  some  similar  method.     Unleavened  bread  requires  much 
more  mastication.     Hot  bread  is  unwholesome,  because  it  is 
not  firm  enough  to  be  thoroughly  masticated,  but  is  converted 
into  a  pasty  heavy  mass,  that  is  not  easily  digested. 


10.  Bread.-  ''The  health  and  power  of  a  nation,  as  of  an  army, 
depend  greatly  on  its  food.  The  quality  of  bread  in  any  nation,  com- 
munity, or  family  is  a  pretty  good  measure  of  itg  civilization.  No  one 
can  entirely  dispense  with  it.  Good  or  bad,  in  some  form  it  must  be  had. 
So  it  is,  and  has  been  from  the  earliest  records  of  the  race,  and  so  it  will 
doubtless  continue.  Leavened  or  fermented  bread  is  as  old  as  the  time 
of  Moses,  and  its  value  has  been  fully  tested.  Whatever  be  the  precise 
action  of  the  leaven,  it  transforms  the  grain  by  partial  decomposition  of 
its  original  elements,  and  leaves  as  its  resultant  what  all  men  in  all  ages 
have  approved.  Is  the  art  of  making  good,  honest,  leavened,  Bible  bread 
lost  in  Massachusetts,  as  some  of  our  friends  declare  ?  Baker's  bread  is 
almost  universally  adulterated.  Bread  hastily  made  in  families  is  mixed 
in  a  variety  of  ways,  with  a  variety  of  chemicals,  and  is  generally  imper- 


24.  Wheat?    " Staff  of  life ?"    White  flour?    Hard-grain  wheats ?    Bolting?    Graham 
bread? 

25.  Leavened  bread ?    Unleavened?    Hot  bread? 


FOOD  AND  DRINK  103 

26.  Wheaten  bread  contains  nearly  every  principle  requisite 
for  sustaining  life,  except  fat.      This  is  commonly  added  in 
other  articles  of  diet,  especially  in  butter,  —  "  bread  and  butter," 
consequently,  forming  an  almost  perfect  article  of  food.     The 
following  experiment  is  recorded :  "  A  dog  eating  ad  libitum  of 
white  bread,  made  of  pure  wheat,  and  freely  supplied  with 
water,  did  not  live  beyond  fifty  days.     He  died  at  the  end  of 
that  time  with  all  the  signs  of  gradual  exhaustion."    Death 
took  place,  not  because  there  was  anything  hurtful  in  the 
bread,  but  because  of  the  "absence  of  one  or  more  of  the  food 
principles. 

27.  The  Potato.  —  The  common  or  Irish  potato  is  the  vege- 
table most  extensively  used  in  this  country  and  Great  Britain. 
Among  the  poorer  classes  in  Ireland  it  is  the  main  article  of 
food.     While  it  is  not  so  rich  in  nutritious  substances  as  many 
others,  it  has  some  very  useful  qualities.     It  keeps  well  from 
season  to  season,  and  men  do  not  weary  of  its  continuous  use. 
it  is  more  than  two-thirds  water,  the  rest  being  chiefly  starch, 
with  a  little  albumen. 

28.  The  sweet  potato  differs  from  the  white  or  common  in 
containing  more  water  and  a  small  proportion  of  sugar.     The 
common  potato  and  the  tomato  belong  to  the  same  botanical 
order  as  the  "  nightshades,"  but  do  not  possess  their  poisonous 

fectly  cooked.  Very  often  the  elements  of  wheat  and  fat  which  the  body 
demands  (a  wise  and  witty  clergyman  of  the  last  generation  used  to  say, 
'bread  is  the  staff  of  life,  but  bread  and  butter  is  a  gold-headed  cane  ') 
are  furnished  in  underdone  pastry,  made  from  flour  and  hog's  lard.  Any 
family  who  will  take  the  pains  can  have  good  bread.  It  involves  not 
more  than  ordinary  skill  and  judgment.  It  is  to  be  found  on  the  con- 
tinent of  Europe,  on  all  the  great  lines  of  travel,  and  is  as  common 
among  the  people  of  France  and  Germany  as  it  is  rare  with  us.  The 
materials  for  an  honest,  wholesome  loaf  are  simple  and  not  expensive. 
The  value  of  time  and  labor  required  for  kneading  the  dough  are  the 
only  difficulties,  and  these  we  would  not  undervalue ;  they  are  in  many 
families  very  serious,  and  not  easily  overcome."  —  Derby  on  the  Food  4 
Massachusetts.  

26.  Wheaten  bread  ?    Bread  and  butter  ?    Experiment  on  the  dog? 

27.  State  what  is  said  of  the  Irish  potato. 

38.  Sweet  potato  ?    Nightshades  ?    Potatoes  when  germinating  ? 


104  FOOD  AND  DRINK 

qualities,  unless  we  except  potatoes  that  are  in  the  process  of 
germination  or  sprouting,  when  they  are  found  injurious  as 
food. 

29.  Fruits.  —  These  are  produced,  in  this  country,  in  great 
abundance,  and  are   remarkable   alike  for  their  variety  and 
delicious   flavor;    consequently  they   are   consumed  in  large 
quantities,  especially  during  the  warmer  months.     The  moder- 
ate use  of  ripe  fruits,  in  their  season,  is  beneficial,  because 
they  offer  a  pleasant  substitute  for  the  more  concentrated  diet 
that  is  used  in  cold  weather.     The  amount  of  solid  nutriment 
they  contain  is,  however,  small.    The  percentage  of  water  in 
cherries  is  seventy-five,  in  grapes  eighty-one,  in  apples  eighty- 
two.     Unripe  fruits  contain  starch,  which,  during  the  process 
of  ripening,  is  converted  into  ^sugar.      Such  fruits   are   indi- 
gestible, and  should  be  avoided;   cooking,  however,  in  part 
removes  the  objection  to  them. 

30.  Pure  Water. — It  is  important  that  the  water  we  drink 
and  use  in  the  preparation  of  food  should  be  pure.     It  should 
be  clear  and  colorless,  with  little  or  no  taste  or  smell,  and  free 
from  any  great  amount  of  foreign  ingredients.      Chemically 
pure  water  does  not  occur  in  nature ;   it  is  obtained  only  by 
the  condensation  of  steam,  carefully  conducted,  and  is  not  as 
agreeable  for   drinking  purposes  as  the  water  furnished  by 
springs  and  streams.      Rain-water  is  the  purest  occurring  in 
nature;   but  even  this  contains  certain  impurities,  especially 
the  portion  which  falls  in  the  early  part  of  a  shower ;  for  in 
its  descent  from  the  clouds,  the  particles  floating  in  the  air  are 
caught  by  the  falling  drops. 

31.  Water  from  springs  and  wells  always  contains  more  or 
less  foreign  matter  of  mineral  origin.      This  imparts  to  the 
drink  its  pleasant  taste  —  the  sparkle,  or  "  life,"  coming  from 
the  gases  absorbed  by  the  water  during  its   passage  under- 

29.   Fruits  ?    Use  of  ripe  fruit  ?    Nutriment  they  contain  ?    Starch  in  unripe  fruits  ? 
Cooking  of  unripe  fruits  ? 

80.  How  should  drinking-water  be  as  regards  color  and  smell  ?    Chemically  pure  water  ? 
How  obtained  ?    Agreeableness  of  perfectly  pure  water  ? 

81.  Spring  and  well  water  ?    Whence  the  sparkle,  or  life  ?    The  water  supply  of  cities  ? 
Croton  water?    Kidgewood? 


FOOD  AND  DRINK  105 

ground.  The  ordinary  supply  of  cities  is  from  some  pure 
stream  or  pond,  conveyed  from  a  distance  through  pipes,  the 
limpid  fluid  containing  generally  only  a  small  amount  of  im- 
purity. Croton  water,  the  supply  of  New  York  City,  is  very 
pure,  and  contains  only  four  and  a  half  grains  to  a  gallon ;  the 
Kidgewood  water,  of  Brooklyn,  holds  even  less  foreign  matter. 

32.  Drinking-water  may  contain  as  large*  a  proportion  as 
sixty  to  seventy  grains  per  gallon  of  impurity,  but  a  much 
larger  quantity  renders  it  unwholesome.     The  mineral  spring 
waters,  used  popularly  as  medicines,  are  highly  charged  with 
mineral  substances.     Some   of  them,  such  as  the  waters  at 
Saratoga,  contain  three  hundred  grains  and  more  to  the  gallon. 
(Bead  Xote  11.) 

33.  Action  of  Water  upon  Lead.  —  The  danger  of  using  water 
that  has  been  in  contact  with  certain  metals  is  well  known. 

11.  Impure  Water  Spreads  Disease.  —  "In  the  year  1867,  three 
millions  of  pilgrims,  of  whom  a  handful  had  come  from  a  cholera  dis- 
trict, assembled  at  Hurdwar,  a  few  miles  from  the  spot  where  the  Ganges 
escapes  from  the  Himalayas.  On  the  12th  of  April  the  three  millions 
resolved  to  bathe  and  drink.  *  The  bathing-place  of  the  pilgrims  was  a 
space  650  feet  long  by  30  feet  wide,  shut  off  from  the  rest  of  the  Ganges 
by  rails.  Into  this  long  and  narrow  inclosure  pilgrims  from  all  parts 
of  the  encampment  crowded  as  closely  as  possible  from  early  morn  to 
sunset ;  the  water  within  this  space,  during  the  whole  time,  was  thick 
and  dirty — partly  from  the  ashes  of  the  dead,  brought  by  surviving 
relatives  to  be  deposited  in  the  water  of  their  river  god,  and  partly  from 
the  washing  of  the  clothes  and  bodies  of  the  bathers.  Now,  pilgrims  at 
the  bathing  ^haut,  after  entering  the  stream,  dip  themselves  under  the 
water  three  times  or  more,  and  then  drink  of  the  holy  water,  whilst 
saying  their  prayer.  The  drinking  of  the  water  is  never  omitted ;  and 
when  two  or  more  members  of  a  family  bathe  together,  each  from  his 
own  hand  gives  to  the  other  water  to  drink.  On  the  evening  of  the  next 
day,  the  13th  of  April,  eight  cases  of  cholera  were  admitted  into  one  of 
the  hospitals  at  Hurdwar.  By  the  15th,  the  whole  of  this  vast  concourse 
of  pilgrims  had  dispersed,'  carrying  the  cholera  in  every  direction  over 
India ;  it  attacked  the  British  troops  along  the  various  routes,  it  passed 
the  northern  frontier,  got  into  Persia,  and  so  on  into  Europe,  where  it 
will  work  its  wicked  will  for  some  time  to  come.  That  is  a  sample  of 
the  mischief  water  can  do  in  the  way  of  spreading  disease."  —  London 
Medical  Press.  

39.   Impurities  in  drinking-water  ?    Mineral  springs  f 
38.  What  is  stated  of  the  action  of  water  upon  lead  ? 


106  FOOD  AND  DRINK 

Lead  is  one  of  the  most  readily  soluble,  and  probably  the  most 
poisonous  of  these  substances  in  common  use.  When  pure 
water  and  an  untarnished  surface  of  lead  come  in  contact, 
the  water  gradually  corrodes  the  metal,  and  soon  holds  an 
appreciable  quantity  of  it  in  solution.  When  this  takes  place 
the  water  becomes  highly  injurious ;  the  purer  the  water,  and 
the  more  recent  the  use  of  the  metal,  the  greater  will  be  the 
danger.  {Read  Note  12.) 

34.  In  cities,  lead  pipes  are  commonly  used  to  convey  water 
through  the  houses ;  lead  being  also  used  in  the  construction  of 
roofs,  cisterns,  and  vessels  for  keeping  water  and  other  liquids. 
After  articles  made  of  lead  have  been  in  use  several  months, 
the  danger  of  lead-poisoning  diminishes.    An  insoluble  coating 
of  the  sulphate  of  lead  forms  upon  the  exposed  surface,  thus 
protecting  it  from  further  corrosion.     It  is,  however,  a  wise 
precaution,  at  all  times,  to  reject  the  water  or  other  fluid  that 
has  been  in  contact  with  leaden  vessels  over  night,  or  for  a 
number  of   hours.     Allow  the  water  in  pipes  to  run  freely 
before  using. 

35.  Coif ee.  —  This  is  an  important  addition  to  diet,  and,  if 
moderately  used,  is  beneficial  to  persons  of  adult  age.     As 
commonly  employed,  it  consists  of  an  infusion  in  boiling  water 
of  the  roasted  and  ground  berry.     The  water  extracts  certain 
flavoring   and  coloring   matters,  but  that  which  gives  it   its 
peculiar  stimulant  qualities  is  the  alkaloid  caffeine.    With  most 
persons  its  action  is  that  of  a '  gentle  stimulant,  without  any 
injurious  reaction.    It  produces  a  restful  feeling  after  exhaust- 

12.  Lead  in  Drinking- Water.  —  "The  danger  of  using  lead  for  pipes 
or  cisterns  is  now  well  known,  the  case  of  the  late  royal  family  of  France, 
at  Claremont,  having  made  the  matter  notorious.  In  this  case  there  was 
one-tenth  of  a  grain  in  the  gallon,  and  one-third  of  the  persons  who 
drank  the  water  were  affected.  But  even  one  one-hundredth  of  a  grain 
per  gallon  has  produced  palsy  in  those  who  drank  this  impurity  habitually. 
It  is  remarkable  that  the  Thames  water  will  at  one  time  dissolve  lead, 
and  not  at  another."  —  Mapother's  Health  Lectures. 


34.  Lead  ia  pipes  and  other  things  ?    Advice  ?    What  takes  place  after  the  articles  of 
lead  have  been  used  much  ?    What  is  wise  ? 

35.  Coffee  as  an  article  of  diet  ?    Of  what  does  it  consist  ?    How  does  the  water  affect 
the  coffee  ?    The  peculiar  stimulant  ?    How  does  it  affect  most  person^  ? 


FOOD  AND  DRINK  107 

ing  efforts  of  mind  or  body ;  it  tranquillizes,  but  does  not  dis- 
qualify for  labor,  and  hence  it  is  highly  esteemed  by  persons 
of  literary  pursuits. 

36.  Another  property  of  coffee  is,  that  it  diminishes  the 
waste  of  the  tissues,  and  consequently  permits  the  performance 
of  excessive  labor  upon  an  economical  and  inadequate  diet. 
This  has  been  tested  among  the  miners  of  Belgium.     Their 
allowance  of   solid  food  was  below  that  found  necessary  in 
prisons  and  elsewhere;  bu£,  with  the  addition  of  about  four 
pints  of  coffee  daily,  they  were  enabled  to  undergo  severe 
labor  without  reducing  their  muscular  strength.    The  caravans 
which  traverse  the  deserts  are  supported  by  coffee  during  long 
journeys  and  lengthened  privation  of  food.     Among  armies  it 
is  indispensable  in  supplementing  their  imperfect  rations,  and 
in  relieving  the  sense  of  fatigue  after  great  exposure  and  long 
marches.     When  taken  with  meals,  coffee  is  also  thought  to 
promote  digestion. 

37.  Tea.  —  The  effects  of  tea-drinking  are  very  similar  to 
those  of  coffee,  and  are  due  to  a  peculiar  principle  called  tlieine. 
This  principle  is  probably  the  same  as  that  found  in  coffee  — 
caffeine  —  since  the  chemical  composition  of  both  is  precisely 
alike.     Tea,  as  a  beverage,  is  made  from  the  dried  leaves  of 
the  plant  by  the  addition  of  hot  water ;  if  the  tea  be  boiled, 
the  oil  which  gives  it  its  agreeable  flavor  is  driven  off  with  the 
steam.     There  are  two  kinds  of  tea — the  black  and  the  green ; 
the  latter  is  sometimes  injurious,  producing  wakefulness  and 
other  nervous  symptoms.     The  excessive  use  of  either  coffee 
or  tea  will  cause  wakefulness. 

38.  During  Dr.  Kane's  expedition  in  the  Arctic  regions,  the 
effects  of  these  articles  were  compared.    "  After  repeated  trials, 
the  men  took  most  kindly  to  coffee  in  the  morning,  and  tea  in 
the  evening.     The  coffee   seemed    to  continue    its    influence 
throughout  the  day,  and  they  seemed  to  grow  hungry  less 


86.  Another  property  of  coffee?  Miners  of  Belgium  ?  The  Caravans?  Among  armies  ? 
Taken  with  meals  ? 

37.  Effects  of  tea-drinking  ?  Peculiar  principle  ?  The  tea  beverage,  how  made  ?  Black 
and  green  tea  ?  Excessive  use  of  tea  or  coffee  ?  * 

88.  Experiments  made  during  Kane's  expedition  ? 


108  FOOD  AND  DRINK 

rapidly  than  after  drinking  tea,  while  tea  soothed  them  after  a 
day's  hard  labor,  and  the  better  enabled  them  to  sleep.  They 
both  operated  upon  fatigued  men  like  a  charm,  and  their  supe- 
riority over  alcoholic  stimulants  was  very  decided." 

39.  Chocolate  is  made  from  the  seeds  of  the  cocoa-tree,  a 
native  of  tropical  America.     Its  effects  resemble  somewhat 
those  of  tea  and  coffee,  but  it  is  very  rich  in  nutriment.     Lin- 
naeus, the  botanist,  was  so  fond  of  this  beverage,  that  he  gave 
to  the  cocoa-tree  the  name  Theobroma  —  "the  Food  of  the 
Gods."    Its  active  principle  is  theobromin. 

40.  Alcohol.  —  The  word  alcohol  is  of  doubtful  origin.    It  is 
commonly  supposed  to  be  derived  from  the  Arabic  language, 
several  words  in  that  tongue  resembling  it  in  sound,  but  none 
of  them  or  any  other  in  the  language  have  a  meaning  corre- 
sponding with  that  of  the  English  term. 

41.  History.  —  Alcohol  was  distilled  from  rice  many  centu- 
ries before  that  seed  was  known  in  Europe.     We  hear  of  it  in 
Bagdad  about  the  year  900.     It  was  known  to  the  Moors  of 
Spain,  through  whom  the  knowledge  of  its  production  spread 
into  Western  Europe.     The  first  description  of  alcohol  was 
given  by  a  western  writer  about  1280,  who  wrote  of  a  "  burning 
or  ardent  water "  that  resulted  from  the  distillation  of  wine. 
It  may  also  have  been  known  to  the  Romans,  for  Pliny,  in 
the  first  century,  wrote  of  a  strong  kind  of  wine  that  was  in- 
flammable —  a  quality  that  strongly  suggests  the  knowledge 
of  a  product  of  distillation. 

42.  The  Alcohols.  —  There  are  at  least  twelve  members  of 
the  alcohol  family,  the  oldest  of  which  is  common  alcohol. 
This  last  is  the  only  one  that  need  be  referred  to  here.     Com- 
mon Alcohol  is  sometimes  known  as  spirit  of  wine,  also  as 
vinic  alcohol.     It  is  commonly  obtained  by  the  distillation  of 
grains  or  of  wine.     The  ardent  spirits  of  commerce  (brandy, 
whiskey,  gin,  and  rum)  contain  about  one  half  water,  the  other 

89.  State  what  is  said  of  chocolate. 

40.  In  what  language  has  the  word  alcohol  its  origin  ? 

41.  Give  its  history .- 

42.  How  is  common  alcohol  obtained  f 


FOOD  AND  DRINK  109 

half  alcohol.  Alcohol  is  also  found  in  all  the  wines  and  malt 
liquors  (beer,  ale,  and  porter)  in  varying  proportions.  The 
juices  of  ripe,  sweet  fruits  will,  at  seventy  degrees  Fahren- 
heit, begin  spontaneously  to  "  work "  or  ferment ;  also  wheat 
and  other  starch-grains,  when  sprouting,  will  have  their  starch 
changed  into  sugar,  and  this,  in  like  manner,  will  undergo 
fermentation — alcohol  being  one  of  the  results  of  this  action 
in  both  cases.  Thus  this  fermentation,  in  changing  barley, 
grapes,  and  apples,  into  beer,  wine,  and  cider,  respectively, 
transforms  valuable  foods  into  most  seductive  poisons. 

43.  Properties  of  Alcohol.  —  Alcohol  is  a  clear,   colorless, 
volatile,   and    inflammable    liquid  of    penetrating   odor  and 
burning  taste.     It  is  lighter  than  water.     As  it  cannot  be 
frozen,  it  is  used  in  thermometers  for  taking  low  or  exceedingly 
cold  temperatures.     It  is  also  used  in  spirit  levels.     It  burns 
with  a  pale,  bluish  flame,  without  smoke,  and  with  intense 
heat ;  hence  its  use  in  the  spirit-lamp. 

44.  Is  Alcohol  Food  ?  —  Some  authorities  class  alcohol  among 
the  food  substances.     Chemically  it  is  allied  to  the  sugars,  but 
the  effect  of  alcohol  within  the  body  is  very  unlike  that  of  the 
sugars.     The  latter  are  nourishing,  while  the  former  tends  to 
impair  nutrition.     It  was  on  the  mistaken  theory  that 'alcohol 
had  sustaining  power,  that  for  two  hundred  years  the  armies 
and  navies  of  certain  countries  were  supplied  with  rations  of 
rum  or  some  other  alcoholic  drink,  under  the  name  of  "grog." 
During  recent  years,  a  systematic  inquiry  has  been  made  to 
discover  whether  the  grog-ration  was  really  serviceable  or  the 
reverse.     Tests  have  been  tried  upon  considerable  bodies  of 
men,  under  military  discipline,  by  withdrawing  that  ration; 
comparisons  have  been  made  at  home  and  abroad,  in  hot  cli- 
mates and  in  cold,  in  active  service  and  at  rest.     The  results 
of  these  observations  have,  without  exception,  been  favorable  to 
the  non-use  of  spirits.     The  proportion  of  ill-health,  the  num- 
ber of  sick  days,  and  the  incapacity  for  work  have  invariably 
been  greater  among  the  men  to  whom  the  spirit-ration  has  been 

43.  What  are  the  properties  of  alcohol  ? 

44.  What  can  you  say  of  alcohol  aa  a  food  t 


110  FOQD  £ND  DRINK 

issued,  the  quality  of  food  and  other  circumstances  being  made 
as  nearly  equal  as  possible.  Hence  the  conclusion  that  not 
only  is  alcohol  not  a  food,  but  is  injurious  in  itself,  and  a 
detriment  to  the  food  taken. 

45.  Does  Alcohol  Relieve  Thirst? — One  of  the  most  striking 
properties  of  alcohol  is  its  affinity  to  water.     When  swallowed, 
therefore,  its  tendency  is  to  deprive  the  body  of  water,  and  to 
create  thirst  rather  than  to  relieve  it.     It  may  then  be  stated 
that  alcoholic  drinks  which  appear  to  quench  thirst  do  so  by 
means  of  the  water  that,  in  greater  or  less  quantities,  dilutes 
the  alcohol  they  contain.     Water,  the  peerless  beverage  of 
nature,  does  its  work  better  in  proportion  as  it  remains  free 
from  alcohol.     To  maintain  normal  action,  the  delicate  organs 
of  the  body  require  a  uniform  supply  of  water.    When  alcohol 
is  introduced,   it  draws  the  water  to  itself,  and  leaves  the 
organs  without  their  share  of  proper  moisture  ;  hence,  after 
death  from  alcoholism,  we  find  them  affected  in  different 
degrees,  being  drier  and  harder  than  is  natural. 

46.  Does   Alcohol   Enable   its   Consumers  to  Resist  Extreme 
Cold?  —  If  this   could   be   proved  to  be  a  fact,  some  of  its 
boasted  usefulness  would  receive  support.      In  extreme  cold 
climates,  the  inhabitants  are  enabled  to  live  comfortably  by 
consuming  vast  quantities  of  animal  food  alone,  especially  if  it 
is  abundantly  oily.     Will  alcohol  act  in  a  similar  way  or  assist 
in  maintaining  heat  ?     Experience  and  observation  say  no. 

47.  Before  the  thermometer  was  applied  to  the  testing  of 
the  body's  temperature,  it  was  commonly  supposed,  by  reason 
of  the  sensations  of  warmth,  that  alcohol  increased  bodily  heat. 
When,  however,  this  new  test  was  applied,  it  became  apparent 
that  those  sensations  were  deceptive,  and  that  there  had  been 
an  actual  fall  in  temperature  as  the  result  of  imbibing  alcohol. 
The  surface  of  the  stomach  is  irritated  by  this  powerful  agent, 
causing  the  nerves  of  sensation  to  convey  to  the  brain  the  im- 
pression that  something  has  entered  the  stomach  which  is  pro- 

45.  Does  alcohol  relieve  thirst  ? 

46.  Does  alcohol  enable  one  to  resist  cold  ? 

47.  How  is  the  temperature  of  the  body  affected  ? 


FOOD  AND  DRINK  111 

ducing  warmth.  This  is  a  delusive  impression,  as  we  know, 
by  pouring  a  few  drops  of  alcohol  on  the  skin,  that  the  ten- 
dency of  alcohol  is  to  cool  the  surface  whenever  evaporation 
can  take  place. 

48.  The  sensation  of  warmth  of  the  face  and  surface  of  the 
body  is  also  deceptive.     The  flushing  of  the  face,  common  to 
hard  drinkers,  does  not  indicate  that  they  have  a  superabun- 
dance of  animal  heat,  the  temperature  of  their  bodies  being 
below  normal.     The  truejcause  of  the  flush  is  a  paralysis  of 
one  set  of  nerves  governing  the  natural  action  of  the  hair-like 
vessels  that  course  just  below  the  skin.     Nature  has  provided 
these  infinitely  fine  vessels  with  minute   controlling  nerves, 
whose  duty  it  is  to  regulate  the  flow  of  blood  in  exposed 
positions.     Alcohol  paralyzes  this  control;  the  blood  flows  at 
random,  and  the  terminal  vessels  are  overcharged  with  blood. 
Hence,  the  high  color,  which  is  so  remarkable   in  habitual 
drinkers  that  it  amounts  to  a  disfigurement,  is  Nature's  signal 
of  distress,  showing  that  the  circulation  is  deranged,  and  the 
blood  unduly  brought  into  contact  with  the  lower  temperature 
of  the  outer  air.     Alcohol,  therefore,  is  not  a  producer  of  heat, 
but  a  promoter  of  cold,  and  must  be  dangerous  to  any  persons 
taking  it  when  they  are  exposed  to  low  temperatures.     (Read 
Note  13.) 

49.  The  testimony  of  those  who  have  had  experience  in 
contact  with  the  realms  of  snow  and  ice  is  unanimous  against 
the  cold-resisting  property  of  alcohol.     It  is  recorded  of  the 
men  who  served  in  Napoleon's  campaign   in   Russia,  under 
great  exposure  to  cold,  that  death  was  hastened  by  the  use  of 
alcohol.     The  evidence  of  the  Monks  of  St.  Bernard  is  similar. 

13.  Dr.  Rae's  Statement.  — "The  Arctic  explorer,  Dr.  Rae,  states 
that  he  found  entire  avoidance  of  alcohol  necessary  in  the  far  North.  The 
moment  a  man  had  swallowed  a  drink  of  spirits,  it  was  certain  that  his 
day's  work  was  nearly  at  an  end.  *  It  was  absolutely  necessary  that  the 
rule  of  total  abstinence  should  be  rigidly  enforced^  if  we  would  accomplish 
our  day's  task.  Any  use  of  liquor,  as  a  beverage,  when  we  had  work  on 
hand,  in  that  terrific  cold,  was  out  of  the  question.'  " 


48.  Of  what  is  the  flushed  face  of  drinkers  the  index  ? 

49.  What  do  travelers  in  cold  countries  say  of  its  use  ? 


112  FOOD  AND  DRINK 

Numerous  Arctic  explorers  testify  that  not  only  is  the  tem- 
porary indulgence  liable  to  result  in  most  serious  consequences, 
but  that  strong,  able-bodied  men  in  the  habit  of  using  alcoholic 
drinks  are  entirely  unfitted  to  resist  the  cold  to  which  they 
must  be  exposed.  The  natives  and  travelers  alike  rely  upon 
fresh  animal  food,  especially  fatty  food,  and  avoid  alcohol  as  a 
danger  to  life.* 

50.  Alcohol  Destructive  to  Life.  —  Instead  of  being  a  pro- 
moter of  life,  as  the  early  alchemists  who  produced  it  hoped 
it  would  be,  alcohol  is  hostile  to  life ;  it  is  a  poison.     Plant 
life  is  speedily  destroyed  when  brought  into  close  contact  with 
it.     The  lower  animals  are  poisoned  by  it.     When  applied 
directly  to  small  insects  and  reptiles,  death  commonly  occurs 
in  a  few  seconds  or  minutes.     It  is  hurtful  to  the  larger  ani- 
mals, and  the  more  intelligent  of  them  appear  to  resent  its 
use  instinctively.     This  is  seen  when  dogs  have  been  forced  to 
take  brandy  in  small  doses  for  some  time.     Instead  of  learn- 
ing to  like  it,  they  gradually  show  a  greater  and  greater  dis- 
like to  it. 

51.  The    Proper    Use    of    Alcohol.  —  Like    opium,    chloral, 
arsenic,   and   many   other    poisons,   alcohol    may  be    rightly 
used,  and  that  is  as  a  medicine.     For  the  relief  of  sickness 
and  feebleness   of   body,   or   conditions   of  unusual   fatigue, 
alcohol  can  be  'beneficially  used  under  the  advice  of  a  physi- 
cian.    Like  the  other   poisons,  it   should  be   definitely   pre- 
scribed and  the  size  and  number  of  the  doses  precisely  ordered 
by  the  physician. 

52.  Errors  in  the  Use  of  Alcohol.  —  If  this  view  of  the  ques- 
tion is  the  correct  one,  how  utterly  foolish  is  the  practice  of 
those  who  are  continually  prescribing  for  themselves  doses  of 
this  poisonous  substance  for  any  trifling  disturbance  of  their 

*  "  Alcohol  is  not  the  warming  cordial  and  invigorating  stimulant  that 
it  is  reputed  to  be,  but  there  is  a  world-full  of  preconceived  opinions  in 
its  favor  that  must  be  met  and  overcome  before  the  true  view  can  make 
its  way.  But  the  truth  must  prevail  at  last.  Its  true  place  is  not  along 


50.  What  is  the  effect  of  alcohol  upon  life  f 

51.  What  is  the  proper  use  of  alcohol  ? 

52.  What  three  errors  mentioned  ? 


FOOD  AXD  DRINK  113 

health.  And  how  much  worse  is  the  practice  of  taking  the 
various  forms  of  alcohol  when  the  person  so  taking  them  is  in 
good  health  and  merely  indulges  in  drinking  for  the  purpose 
of  bringing  about  a  temporary  stimulation.  And  worse  than 
all  the  others  is  the  practice  of  Chose  who  not  only  indulge  in 
these  stimulants  themselves,  but  who  ask  others  to  join  in 
with  them  under  the  name  of  good-fellowship,  when  none  of 
them  are  to  be  benefited  by  so  doing,  but  rather  all  of  them 
are  in  danger  of  being  injui^d  by  the  act. 

53.  This   practice,   last   referred   to,   is   often   mistakenly 
spoken  of  as  a  sign  of  generosity,  and  is  ordinarily  called 
"treating."     It   is  wholly  indefensible  from  a  physiological 
point  of  view,  being  harmful  both  to  body  and  mind;  and 
from  a  social  point  of  view  is  without  its  equal  for  the  evil 
that  it  has  wrought  and  is  capable  of  working.     The  "social 
glass  "  and  the  "  treat  at  the  bar  "  count  a  hundred  victims  to 
every  other  single  one  that  can  be  traced  to  any  other  mistaken 
practice  of  human  society.     It  is  in  regard  to  the  evils  that 
flow  from  this  false  show  of  generosity  and  geniality  that  the 
minds  of  the  young  should  early  be  instructed.     It  is  a  well- 
established  fact  that,  in  some  people,  alcohol  has  the  power  to 
create  a  craving  for  more.     Their"  nervous  systems  become  so 
easily  poisoned  by  its  use  that  they  must  have  more,  and  they 
have  not  the  will-power  to  resist  the  temptation.     This  ten- 
dency to  be  so  easily  poisoned  is  also  hereditary  in  some  fami- 
lies, producing  drunkards  for  several  generations. 

54.  Moderation  Societies.  —  "  Moderation  societies  "  have  been 
organized  to  check  the  evils  of  "  treating,"  but  they  have  not 
met  with  success,  and  it  is  not  to  be  expected  that  they  will, 
for  there  can  be  no  moderation  in  the  use  of  this  dangerous 
drug  except  in  the  way  mentioned  at  the  beginning  of  this  sec- 
tion, namely,  as  a  prescribed  medicine.     As  Dr.  Alden  has 

with  the  displays  of  wealth  and  luxury  upon  our  sideboards,  but  in  the 
medicine-chest  along  with  hasheesh,  henbane,  opium,  stramonium,  and 
so  forth,  labeled  as  a  POISON  !  "  —  Dr.  A.  F.  Kinne. 


53.  What  is  said  of  treating  »    Is  alcohol  deceptive  ? 

54.  Wluit  is  said  of  moderation  societies  ? 


114  FOOD  AND  DRINK 

said,  "There  is  no  such  thing  as  a  temperate  use  of  spirits. 
In  any  quantity  they  are  an  enemy  to  the  human  constitution. 
Their  influence  upon  the  physical  organs  is  unfavorable  to 
health.  They  produce  weakness,  not  strength;  sickness,  not 
health;  death,  not  life." 

55.  Diminished  Use  of  Alcohol  as  Medicine.  —  As  a  medicine, 
alcohol  is  far  less  freely  used  by  physicians  now  than  formerly. 
The  dangers  from  its  use  are  more  generally  recognized,  and 
other  remedies  have  been  discovered  and  brought  into  use  that 
are  fully  as  efficient  and  active,  but  have  not  the  tendency  to 
habit-forming  that  is  so  peculiar  to  alcohol  and  other  narcotics. 
There  are  able  physicians  who  refuse  to  employ  any  form  of 
alcohol  as  stimulant  or  medicine,  in  the  belief  that  it  can  be 
safely  and  happily  replaced  by  other  remedies.     In  London 
and  some  other  cities,  hospitals  have  recently  been  organized 
and  are  now  being  operated  011  the  basis  of  total  abstinence 
from  alcoholic  treatment.     In  many  parts  of  England  the  use 
of  alcohol  has  greatly  declined  in  the  alms-houses  and  other 
public  institutions,  in  which  formerly  the  amount  of  stimu- 
lants annually  consumed  was  very  great. 

56.  It  is  well  known  that  alcohol  is  an  ingredient  in  many 
of  the  "Bitters"  and  other  so-called  patent  medicines  that 
have  come  into  popular  use  through  advertisement  in  the 
newspapers.     Many  persons  have  been  deluded  into  the  use  of 
these,  to  them,  doubly  bitter  substances;  for,  not  only  have 
they  not  found  the  curative  results  falsely  proclaimed  in  the 
papers,  but  they  have  been  beguiled  into  habits  of  drinking 
and  into  a  liking  for  alcohol  that  the  "Bitters"  soon  fail  to 
satisfy. 

57.  Concerning  the  Purity  of  Alcoholic  Beverages.  — It  is  well 
known  that  many  makers  and  friends  of  wines  and  liquors 
claim  that  when  these  articles  are  pure  they  are  not  injurious, 
but  that  they  become  hurtful  after  they  leave  their  place  of 
manufacture  by  reason  of   the  impurities  that  are  added  to 
them  by  unscrupulous  dealers.     "  Pure  and  good  liquor,"  they 

55.  Is  alcohol  as  highly  valued  in  medicine  now  as  formerly  ? 

56.  The  effect  of  Bitters  ? 

57.  What  do  wine-dealers  say  ?    What  is  the  harmful  element  t 


FOOD  AND  DRINK  115 

say,  "does  no  harm."  Is  this  correct?  It  cannot  be  denied 
that  deadly  additions  have  been,  and  may  be,  so  made  that 
these  beverages  will  become  more  speedily  and  manifestly 
poisonous  than  they  would  otherwise  be,  but  the  teaching  of 
modern  physiology  is  this :  that  so  long  as  the  main  element 
of  danger — -that  same  alcohol  from  which  they  get  their 
stimulating  and  seductive  properties  —  is  present,  the  ques- 
tion of  purity,  or  age,  or  .smoothness  of  taste  is  one  of  little 
importance.  The  "unclean  thing,"  as  the  Bible  calls  it,  is 
present  in.  all  intoxicants,  whether  they  be  old  and  costly,  or 
cheap  and  new  and  fiery  to  the  taste.  (Read  Note  14.) 

58.  This  so-called  "  purity  "  is  commonly  an  accompaniment 
of  high  cost,  especially  as  applied  to  wines,  and  represents 
money  or  capital  that  has  long  been  lying  idle  in.  order  that 
the  commodities  in  question  may  acquire  "  age  "  and  smooth- 
ness to  the  palate.  "  Purity  "  is  therefore  largely  the  cry  of 
the  seller,  who  is  anxious  to  get  back  his  invested  capital,  with 
interest,  or  perhaps  with  usury.  It  should  be  clearly  under- 
stood that  the  best  of  these  drinks,  even  though  obtained  from 
the  vineyards  or  wine-cellars  of  princes,  are  injurious,  and  that 
the  word  "  purity  "  is,  in  the  light  of  science,  a  misnomer  when 
applied  to  any  beverage  that  contains  alcohol.  (Read  Note  15.) 

14.  Adulteration  in  Liquors.  —  "  It  is  not  enough  that  alcoholic  drinks 
are  dangerous  when  purely  made,  but  there  is  an  added  danger  growing 
out  of  the  almost  universal  practice  of  the  manufacturers  of  these  drinks 
to  tamper  with  them  and  adulterate  them  with  other  harmful  materials. 
Not  many  months  ago  the  city  government  of  Paris  caused  a  testing  of 
all  the  wines  that  were  brought  into  the  market  during  a  month  ;  there 
were  1,518  samples  of  F/encb  wine  examined,  and  only  65  found  abso- 
lutely free  from  injurious  addition — that  is,  less  than  5  per  cent,  was 
really  pure."  —  N.  Y.  Scientific  Times. 

15.  Adulteration  of  Wine.  — The  difficulty  in  the  way  of  getting  pure 
wine  is  nothing  new.  Pliny,  who  lived  eighteen  hundred  years  ago,  wrote 
the  following  complaint :  "Let  us  suppose  that  we  all  agree  as  to  what 
wine  is  the  best,  how  shall  we  get  it  ?  Our  very  princes  do  riot  drink 
pure  wine  ;  to  such  a  point  has  the  villainy  of  the  producers  and  sellers 
of  wine  arrived  that  we  can  buy  nothing  more  than  the  name  of  a 
vintage  —  from  the  very  wine-vat  it  is  all  adulterated  —  and  so,  marvellous 
to  tell,  we  may  say  of  wine,  the  poorer,  the  purer." 


68.   What  is  said  of  purity  as  a  commercial  term  ? 


116  FOOD  AND  DRINK 

QUESTIONS    FOR   TOPICAL   REVIEW 

PAGE 

1.  How  is  the  necessity  for  food  shown  ? 91 

2.  To  what  process  of  waste  and  repair  is  the  body  constantly  subjected  ?  91,  92 

3.  How  do  you  account  for  the  sensations  of  hunger  and  thirst? 92,  93 

4.  What  further  can  you  state  having  relation  to  the  subject? 92 

5.  What  can  you  state  in  regard  to  the  quantity  of  food  required  for 

the  support  of  life  ? 93,  94 

6.  What  circumstances  change  the  needs  of  persons,  old  and  young,  as 

regards  food  and  drink  ? 93 

7.  What  becomes  of  all  the  food  and  drink  we  consume  ? 95 

8.  What  further  can  you  state  in  relation  to  the  process  of  renovation 

through  which  the  body  passes  ? 95 

9.  What  can  you  state  of  the  habit  of  nations  in  respect  to  diet  ? 95,  96 

10.  What  in  relation  to  the  selection  of  articles  for  food  ? 96 

11.  What  has  been  proved  as  regards  animal  food  ? 96 

12.  What  as  respects  the  necessity  for  changing  or  varying  the  diet  ?  . .  96,  97 

13.  Of  what  importance  is  milk  as  an  article  of  food  ? 97,  98 

14.  What  are  the  constituents  of  milk  ? 98 

15.  What  can  you  state  of  eggs  as  an  article  of  food  ? 98 

16.  Of  the  meats,  so  called,  as  an  article  of  food  ? 98 

17.  What  effect  does  cold  have  upon  meats  ? 99 

18.  In  what  other  way  may  beef  and  pork  be  preserved  ? 99 

19.  What  can  you  state  of  salted  meat  as  food,  and  of  its  continued  use  ?        99 

20.  What  change  does  meat  undergo  in  the  cooking  ? 99-101 

21.  What  directions  are  given  for  boiling  meat  ? 100 

22.  What  for  roasting,  and  with  what  results  ? 100,  101 

23.  What  is  said  about  the  frying  of  meats  ? 101 

24.  Give  the  statement  in  relation  to  trichina 101 

25.  State  what  is  said  in  relation  to  fish 101 

26.  What  is  stated  of  the  usefulness  and  other  properties  of  the  prod- 

ucts of  the  vegetable  kingdom  ? 101,  102 

27.  What  further  is  said  of  vegetable  food  ? 101,  102 

28.  Why  is  bread  made  of  wheat-flour  so  important  as  an  article  of  food  ?      102 

29.  State  whatever  else  you  can  in  relation  to  bread 102,  103 

30.  Give  the  statement  respecting  the  potato 103,  104 

31.  What  is  stated  of  fruitsf  the  use  of  them,  their  nutritious  qualities, 

etc.  ? 104 

32.  How  general  is  the  existence  of  perfectly  pure  water  ? 104,  105 

33.  What  is  stated  in  relation  to  drinking  water  ? 105 

34.  What  effect  has  the  action  of  water  upon  lead  ? 105,  106 

35.  What  further  can  you  state  on  the  subject  ? 106 

36.  What  properties  has  coffee  as  an  article  of  diet? 106,  107 

37.  In  what  circumstance  has  coffee  been  found  peculiarly  beneficial?.       107 

38.  What  comparison  is  made  between  coffee,  tea,  and  chocolate  ?  . . .  107,  108 

39.  How  are  the  wines,  and  malt,  and  other  alcoholic  beverages  pro- 

duced ? " 108,  109 

tO.  What  articles  are  employed  in  their  production  ? 109 

41.  What  are  the  properties  of  alcohol  ? 109 

42.  Is  aloohol  a  food  ? 109,  110 

43.  What  is  said  of  the  property  of  alcohol  to  relieve  thirst  ? 110 

44.  What  effect  does  alcohol  have  upon  the  body's  temperature? 110,  111 

45.  What  is  the  cause  for  flushing  of  face  in  drinkers  ? Ill 

46.  What  is  the  testimony  of  Arctic  explorers  and  others? Ill 

47.  "What  is  the  effect  of  alcohol  upon  plant  and  animal  life  ? ,. . . .       112 

48.  What  are  the  only  conditions  for  use  of  alcohol  ? 112 


CHAPTER  VI 

DIGESTION 

The  Principal  Processes  of  Nutrition  —  The  General  Plan  of  Digestion 
—  Mastication  —  The  Teeth  —  Preservation  of  the  Teeth  —  A  ction  of 
the  Saliva —  The  Stomach  and  the  Gastric  Juice —  The  Movements  of 
the  Stomach  —  Gastric  Digestion  —  The  Intestines  —  The  Bile  and 
Pancreatic  Juice  —  Intestinal  Digestion  —  Absorption  by  Means  of 
Blood-vessels  and  Lacteals — The  Lymphatic  or  Absorbent  System  — 
The  Lymph  —  Conditions  which  affect  Digestion —  The  Quality,  Quan- 
tity, and  Temperature  of  the  Food —  The  Influence  of  Exercise  and 
Sleep —  The  Kidneys —  The  Spleen  —  Effect  of  Alcohol  on  Digestion, 
the  Liver,  and  Kidneys 

1.  Nutrition.  —  The  great  design  of  food  is  to  give  nutriment 
or  nourishment  to  the  body.  But  this  is  not  accomplished 
directly,  as  the  food  must  first  pass  through  certain  preparatory 
changes,  as  follows :  (1),  Digestion,  by  which  the  food  is  reduced 
to  a  soluble  condition;  (2),  Absorption,  by  which,  when  digested, 
it  is  taken  into  the  blood ;  (3),  Circulation,  which  carries  the 
enriched  blood  to  the  various  parts  of  the  system;  and  (4), 
Assimilation,  by  which  each  tissue  selects  from  the  blood  the 
materials  necessary  for  its  support. 

"The  human  body,  unlike  all  other  machines,  keeps  itself  in  repair 
without  any  apparent  effort,-  when  proper  food  is  taken  into  the  body. 
If*  the  functions  and  composition  of  food  were  more  clearly  understood, 
there  would  be  fewer  cases  of  failing  health  in  youth  and  middle  age  than 
we  now  have.  There  are  some  persons  who  realize  the  importance  of  this 
knowledge,  and  live  '  by  rule '  to  such  an  extent,  that  they  fail  to  enjoy 
the  food  which  is  so  bountifully  provided  for  us.  We  must  gain  all  the 
knowledge  we  possibly  can  upon  the  subject,  and  learn  to  use  it  wisely ; 
without  neglecting  the  natural  guides  with  which  we  are  gifted."  —  E. 
RICE.  

1.  Design  of  food  ?    How  accomplished  f 

117 


118  DIGESTION 

2.  By  these  four  ste~ps  the  sustaining  power  of  food  is  gradu- 
ally brought  into  exercise  and  the  vital  machinery  kept  in 
working  order,  somewhat  after  the  manner  of  the  steam-engine. 
To  operate  the  latter,  the  force  imprisoned  within  the  coal  and 
water  is  set  free  and  converted  into  motion  by  the  burning 
of  the  fuel  and  the  vaporization  of  the  water.     It  will  be  seen, 
however,  when  we  come  to  study  these  operations  in  the  human 
body,  that  they  are  conducted  silently  and  harmoniously,  with 
marvellous  delicacy  and  completeness,  and  without  that  friction, 
and  consequent  loss  of  power,  which  attend  the  working  of 
the  most  perfect  machinery  of  man's  invention. 

3.  Glands.  —  Situated  in  all  parts  of  the  body  are  certain 
organs,  called  glands,  which  aid  the  work  of  nutrition  in  its 
various  stages.     Each  gland  consists  of  many  active  cells,  all 
alike  in  general  structure  and  function.     These  cells  may  be 
compared   to  the  skilled  laborers  in  a  large  factory.     Like 
these,  the  cells  take  the  "  raw  material,"  as  it  comes  to  them 
through  the  blood  and  lymph,  separate  it,  and  excrete  on  their 
free  surface  the   finished  product.      This  general  process  is 
called  secretion. 

4.  The  product  of  the  salivary  glands  is  called  saliva,  that 
of  the  liver  is  called  bile,  that  of  the  lachrymal  glands  is 
called  tears,  and  so  on.     It  is  evident  that  if  much  material 
is  to  be  secreted  by  a  gland,  many  working  cells  are  neces- 
sary.    In  order  that  many  cells  may  be  brought  into  as  small 
a  space  as  is  possible,  they  are  arranged  on  the  surface  of  a 
tube  or  sack.     Glands  are  of  two  types,  tubular  and  racemose. 
If  the  general  plan  of  arrangement  is  that  of  a  tube,  either 
simple   or   compound,  the   gland   is   called  a   tubular   gland. 
The  perspiratory  glands  are  good  examples  of  this  type.     If 
the   cells   are   arranged  along  a  surface  which  swells  out  at 
its  upper  end,  like  a  sack,  the  gland  is  called  sacular  or  race- 
mose.    The  sebaceous  glands  are  racemose.     Either  type  may 
be  simple  or  compound. 

2.  Sustaining  power  of  food  ?    Simile  of  the  engine  ?    Operation  in  the  human- body  ? 

3.  Use  of  glands?    Constitution?    What  is  the  process  of  secretion  ? 

4.  What  is  the  product  of  the  salivary  glands  called  ?    Of  the  liver  2    Of  the  lachrymal 
glauds  ?    Name  the  two  types  of  glands. 


DIGESTION 


119 


5.  General  Plan  of  Digestion. — The  great  change  which  food 
undergoes  in  digestion  is  essentially  a  refining  process,  re- 
ducing articles  of  diet,  which  are  at  first  more  or  less  solid, 
crude,  and  coarse,  to  a  liquid  and  finely  comminuted' condition, 

suitable  for  absorption  into  the  blood. ' 
The  entire  process  of  digestion  takes 
place  in  what  is  called  the  "  alimen- 
tary canal,"  a  narrow,  crooked  tube, 
about  thirty  feet  in  its  entire  length. 
This  canal  begins  in  the  mouth,  ex- 
tends thence  downward  through  the 
gullet  to  the  stomach  (a  receptacle  in 
which  the  principal  work  of  digestion 
is  performed),  and  thence  onward 
through  the  small  and  large  intes- 
tines. 

6.  The  stomach  and  intestines  are 
situated  in  the  cavity  of  the  abdomen 
(Fig.  22,  C,  and  Fig.  28),  and  occupy 
about  two-thirds  of  its  space.     The 
action  to  which  the  food  is  subjected 
in  these  organs   is  of  two  kinds  — 
mechanical   and  chemical.      By  the 
former  it  is  softened,  agitated,  and 

FIG.  2-2. -SEC™*  OF  TH*TRtTNK,  carried   onward  from   one   point   to 
SHOWING  THE  CAVITIES  OF  THE  another  i  by  the  latter  it  is  changed 

CHEST  AND  ABDOMEX 

A,  chest  c,  Abdomen        m  form  through  the  solvent  power  of 

B,  Diaphragm       D,  Spinal  Column  the  VariOUS  digestive  fluids. 

E,  Spinal  Cord 

7.  Mastication.  —  As  soon  as  solid 

food  is  taken  into  the   mouth,  it  undergoes   mastication   or 
chewing.     It  is  caught  between  the  opposite  surfaces  of  the 
teeth,  and  by  them  is  cut  and  crushed  into  very  small  frag- 
ments.    In  the  movements  of  chewing,  the  lower  jaw  plays 
the  chief  part;  the  upper  jaw,  having  almost  no  motion,  acts 

5.  Change  of  food  in  digestion  ?    Process  of  digestion  ?    Describe  the  alimentary  canal. 

6.  Situation  of  the  stomach  and  intestines  ?    Action  of  the  food  ?    Mechanical  action  ? 
Chemical ': 

7.  Describe  the  process  of  mastication.     How  many  and  what  movements  ? 


120 


DIGESTION 


simply  as  a  point  of  resistance,  to  meet  the  action  of  the 
former.  These  movements  of  the  lower  jaw  are  of  three 
sorts :  an  up-and-down  or  cutting,  a  lateral  or  grinding,  and 
a  to-and-fro  or  gnawing  motion. 

8.   The  teeth  are  composed  of  a  bone-like  material  called 
dentine,  and  are  held  in  place  by  roots  running  deep  into  the 
v  jaw.     The  exposed  portion,  or 

"  crown,'7  is  protected  by  a  thin 
layer  of  enamel  (Fig.  23,  a),  the 
hardest  substance  in  the  body, 
and,  like  flint,  is  capable  of 
striking  fire  with  steel.  In  the 
interior  of  each  tooth  is  a  cavity, 
containing  blood-vessels  and  a 
nerve,  which  enter  it  through  a 
minute  opening  at  the  point  of 
the  root  (Fig.  25). 

9.  There  are  two  sets  of 
teeth :  first,  those  belonging  to 
the  earlier  years  of  childhood, 
called  the  milk  teeth,  which 
are  twenty  in  number  and  small. 
At  six  or  eight  years  of  age, 
when  the  jaw  expands,  and 
when  the  growing  body  requires 
a  more  powerful  and  numerous 
set,  the  roots  of  the  milk  teeth 
are  absorbed,  and  the  latter  are  "  shed/7  or  fall  out,  one  after 
another  (Fig.  24),  to  make  room  for  the  permanent  set. 

10.  There  are  thirty-two  teeth  in  the  permanent  set,  an 
equal  number  in  each  jaw.  Each  half-jaw  has  eight  teeth, 
similarly  shaped  and  arranged  in  the  same  order;  thus,  two 
incisors,  one  canine,  two  bicuspids,  and  three  molars.  The 
front  teeth  are  small,  sharp,  and  chisel-edged,  and  are  well 
adapted  for  cutting  purposes ;  hence  their  name  incisors.  The 

8.  Composition  of  the  teeth  ?    Enamel  of  the  teeth  ?    Interior  of  the  teeth  ? 

9.  The  milk  teeth  ?    The  permanent  teeth  ? 

10, 11.  The  number  of  the  teeth  ?    How  arranged  ? 


FIG.  23.  —  SECTION  or  A  TOOTH 

a,  Enamel ;  ft,  Cavity  ;  c,  c,  Roots : 

d,  Body  of  the  Tooth 


DIGESTION 


121 


canines  stand  next,  one  on  each  side  of  the  jaw;  these  receive 
their  name  from  their  resemblance  to  the  long,  pointed  tusks 
of  the  dog.  (Fig.  25). 

11.  The  bicuspids,  next  in  order,  are  larger  and  have  a 
broader  crown  than  the  former;  while  behind  them  are  the 
molars,  the  largest  and  most  powerful  of  the  entire  set.  These 


2'    1' 


FIG.  24. —SECTION  OP  THE  JAWS 
I'  2'  3'  4'  5',  The  Milk  Teeth  ;  1*  to  8",  The  Germs  of  the  Permanent  Set 

large  back  teeth,  or  "  grinders,"  present  a  broad,  rough  surface, 
suitable  for  holding  and  crushing  the  food.  The  third  molar, 
or  «  wisdom  tooth,"  is  the  last  to  be  cut,  and  does  not  appear 
until  about  the  twenty-first  year.  The  arrangement  of  the 
teeth  is  indicated  by  the  following  dental  formula : 

-3 


c/N, 


122  DIGESTION" 

12.  It  is  interesting,  at  this  point,  to  notice  the  different 
forms  of  teeth  in  different  animals,  and  observe  how  admirably 
their  teeth  are  suited  to  the  respective  kinds  of  food  upon 
which  they  feed.  In  the  carnivora,  or  flesh-feeders,  the  teeth 
are  sharp  and  pointed,  enabling  them  both  to  seize  their  prey 


FIG.  25.  — SECTION  OP  THE  JAWS  — EIGHT  SIDE 

V,  A,  N,  Veins,  Arteries,  and  Nerves  of  the  Teeth.  The  root  of  one  tooth  In  each  jaw  is 
cut  vertically  to  show  the  cavity  and  the  blood-vessels,  etc.,  within  it.  1  to  8,  Perma- 
nent Teeth 

and  tear  it  in  pieces ;  while  the  herbivora,  or  vegetable-feeders, 
have  broad,  blunt  teeth,  with  rough  crowns,  suitable  for  grind- 
ing the  tough  grasses  and  grains  upon  which  they  feed. 

12.  Different  forms  of  teeth  ?    Human  teeth  ?    The  inference? 


DIGESTION  123 

Human  teeth  partake  of  both  forms ;  some  of  them  are  sharp, 
and  others  are  blunt ;  they  are  therefore  well  adapted  for  the 
mastication  of  both  flesh  and  vegetables.  Hence  we  infer 
that,  although  man  may  live  exclusively  upon  either  vegetable 
or  animal  food,  he  should,  when  possible,  choose  a  diet  made 
up  of  both  varieties. 

13.  Preservation  of  the  Teeth.  —  In  order  that  the  teeth  shall 
remain  in  a  sound  and  serviceable  condition,  some  care  is  of 
course   requisite.      In  the*  first   place,  they  require  frequent 
cleansing;  for  every  time  we  take  food,  some  particles  of  it 
remain  in  the  mouth,  and  these,  on  account  of  the  heat  and 
moisture  present,  soon  begin  to  putrefy.     This  not  only  ren- 
ders the  breath  very  offensive,  but  promotes  decay  of  the  teeth. 

14.  The   saliva,  or  moisture  of    the   mouth,   undergoes  a 
putrefactive  change,  and  becomes  the  fertile  soil  in  which  a 
certain  minute   fungus   has   its    growth.     This  fluid,  too,   if 
allowed  to  dry  in  the  mouth,  collects  upon  the  teeth  in  the 
form  of   an  unsightly,  yellow  concretion,  called  tartar.     To 
prevent  this  formation,  and  to  remove  other   offensive  sub- 
stances, the  teeth  should  be  frequently  cleaned  with  water, 
applied  by  means  of  a  soft  tooth-brush.     The  prevention  of 
the  tartar  fungus  is  best  effected  by  the  use  of  a  weak  solution 
of  carbolic  acid.     (Read  Note  1.) 

1.  The  Proper  Care  of  the  Teeth.  —  "  It  is  an  important  question  how 
to  care  for  the  molars.  To  this  end  the  cardinal  maxim  is  cleanliness ; 
and  again  cleanliness.  One  means  of  cleansing  is  the  natural  one  —  that 
is,  by  chewing  food  ;  for  it  is  well  known  that  if  we  have  a  tooth  so  situ- 
ated in  the  jaw  that  it  is  seldom  brought  into  use,  that  tooth  early  shows 
signs  of  decay.  But  more  effectual  is  the  artificial  means — the  brush. 
Children  should  early  be  taught  to  use  this  ;  and  for  them  a  softer  brush 
should  be  selected  than  for  adults.  They  should  also  early  be  taught  to 
use  no  metallic  substances,  as  pins,  needles,  etc.,  to  remove  substances 
from  between  the  teeth.  The  teeth  should  always  be  thoroughly  cleansed 
after  taking  acids  into  the  mouth  —  for  they  are  the  great  enemies  to  the 
teeth  —  and  also  after  candies  and  other  forms  of  sugar,  for  theiB  particles 
that  linger  on  the  teeth  are  changed  by  decomposition  into  lactic  acid. 
Occasional  examination  of  the  teeth  is  prudent,  in  order  that  a  com- 
mencing cavity  may  be  promptly  detected  and  remedied.  Teeth  that  are 

18.  Cleaning  of  teeth  ?    Effects  of  not  cleaning  ? 

14.  Effects  of  the  saliva  ?    Formation  of  tartar  ?    How  prevented  ?    How  destroyed  ? 


124 


DIGESTION 


15.  It  should  be  borne  in  mind  that  the  enamel,  Kature's 
protection  for  the  teeth,  when  once  destroyed,  is  never  formed 
anew ;  and  the  body  of  the  tooth  thus  exposed  is  liable  to  rapid 
decay.     On   this   account,  certain   articles  are  to  be  guarded 
against;    such  as   sharply  acid   substances   that   corrode   the 
enamel,  and   hard   substances   that   break  or  scratch  it  —  as 
gritty  tooth-powders,  metal  tooth-picks,  and  the  shells  of  hard 
nuts.     Sudden  alterations  from  heat  to  cold,  when  eating  or 
drinking,  also  tend  to  crack  the  enamel.  t 

16.  Action  of  the  Saliva. — While  the  morsel  of  food  is  cut 
and  ground  by  the  teeth,  it  is  at  the  same  time  intimately 

mixed  with  the  saliva,  or 
fluids  of  the  mouth.  This 
constitutes  the  second  step 
of  digestion,  and  is  called 
insalivation.  The  saliva, 
the  first  of  the  digestive 
solvents,  is  a  colorless, 
watery,  and  frothy  fluid. 
It  -is  secreted  (i.e.,  sepa- 
rated from  the  blood) 
partly  by  the  mucous 
membrane  which  lines  the 
mouth,  but  chiefly  by  the 
salivary  glands  situated  near  the  mouth. 

17.  The  parotid  glands  lie   below  and  in  front  of  the  eur. 
Mumps  is  an  inflammation  of  these  glands.     Each  opens  by  a 
duct  into  the  mouth  near  the  second  upper  molar  tooth.     The 
submaxillary  glands  are  situated  near  the  angles  of  the  lower' 
jaw,  at  the  base  of  the  tongue.     They  have  a  single  duct  which 
opens   into  the  mouth   beneath   the   tongue.     The   sublingual 
glands  are  the  smallest  of  the  three  pairs,  and  lie  just  beneath 
the  forward  end  of  the  tongue.     They  open  into  the  floor  of 
the  mouth  by  several  ducts. 

decayed  beyond  the  remedy  by  filling  should  be  immediately  removed." 
—  Lane  on  the  Hygiene  of  the  Teeth. 


FIG.  26.  —  STRUCTURE  OF  A  SALIVARY  GLAND 


16,  Care  of  enamel  ?  16.  What  is  saliva  ?    17.  Name  four  kinds  of  glands. 


DIGESTION 


125 


18.  These  glands  consist  of  clusters  of  very  small  pouches, 
around  which  a  delicate  network  of  blood-vessels  is  arranged ; 
they  empty  into  the  mouth  by  means  of  little  tubes,  or  ducts. 
The  flow  from  these  glands  is  generally  sufficient  to  maintain 
a  soft  and  moist  condition  of  the  tongue  and  mouth ;  but  when 

they  are  excited  by  the  pres- 
ence and  taste'  of  food,  they 
pour  forth  the  saliva  more 
freely.  Even  the  mere  thought 
of  food  will  at  times  cause  the 
saliva  to  flow,  as  when  the  ap- 
petite is  stimulated  by  the 
sight  or  smell  of  some  savory 
article;  so  that  the  comnon 
expression  is  correct  that  "  the 
mouth  waters  "  for  the  favorite 
FIG.  27.— THE  HEAD  OF-  A  HOBSE,  show-ing  articles  of  food.  Anxiety  and 

the  large  salivary  gland  (a),  its  duct  (6),  the        -i;     ™pvpnf-     if«j     flow      unrl 
muscles  of  mastication  (c,  d,  e,  f,  and  g)          &ri(  IOW>     aml 

cause  "  the  tongue  to  cleave  to 

the  roof  of  the  mouth."  In  the  horse,  and  other  animals  that 
feed  upon  dry  and  coarse  fodder,  and  require  an  abundant 
supply  of  saliva,  we  find  large  salivary  glands,  as  well  as 
powerful  muscles  of  mastication. 

19.  The  mingling  of  the  saliva  with  the  food  seems  a  simple 
process,  but  it  is  one  that  plays  an  important  part  in  digestion. 
In  the  first  place,  it  facilitates  the  motions  of  mastication,  by 
moistening  the  food  and  lubricating  the  various  organs  of  the 
mouth.     Secondly,  it  prepares  the  way  for  other  digestive 
acts :  by  the  action  of  the  teeth,  the  saliva  is  forced  into  the 
solid  food,  softens  the  harder  substances,  and  assists  in  con- 
verting the  whole  morsel  into  a  semi-solid,  pulpy  mass,  that 
can  be  easily  swallowed,  and  readily  acted  upon  by  other 
digestive  fluids.     The  saliva,  also,  by  dissolving  certain  sub- 
stances, as  sugar  and  salt,  develops  the  peculiar  taste  of  each ; 
whereas,  if  the  tongue  be  dried  and  coated,  they  are  taste- 
is.   The  flow  of  saliva  ?    The  thought  of  food  f    Anxiety  and  grief?    Animals  fed  upon 

dry  and  coarse  food  ? 

19.   Importance  of  the  process  ?    The  first  place  ?    The  second  ?    The  third  ? 


126  DIGESTION 

less.    Hence,  if  substances  are  insoluble,  they  are  devoid  of 
taste. 

20.  Finally,  the  saliva  has  the  property  of  acting  chemically 
upon  the  food.  As  we  have  before  stated  (Chap.  IV.),  starch, 
as  starch,  cannot  enter  the  tissues  of  the  body ;  but,  in  order  to 
become  nutriment,  must  first  be  changed  to  grape-sugar.  This 
change  is,  in  part,  effected  by  the  saliva,  and  takes  place  almost 
instantly,  whenever  it  comes  in  contact  with  cooked  starch. 
This  important  function  is  due  to  an  organic  ingredient  of  the 
saliva  called  ptyalin.  This  substance  has  been  extracted  from 
the  saliva  by  the  chemist,  and  has  been  found,  by  experiment, 
to  convert  into  sugar  two  thousand  times  its  own  weight  of 
starch.  (Read  Notes  2  and  3.) 

2.  The  First  Step  of  Digestion.  —  "  The  digestive  process  begins  in 
the  mouth  ;  among  civilized  people  it  begins  in  the  plate,  or  even  before. 
Undoubtedly  mastication  is  the  natural  method  of  mincing  meat,  and  not 
the  least  of  its  value  lies  in  the  faet  that  it  takes  time.    A  man  who  is 
eating  a  tough,  and  therefore  not  very  digestible  chop,  will  be  slow  in 
eating,  if  he  is  careful  to  masticate  it  well.     There  will  be  a  long  interval 
between  each  mouthful,  and  the  stomach  will  run  no  risk  of  being  hastily 
loaded. 

"  Now,  a  hastily-loaded  stomach  is  as  bad  almost  as,  or,  rather,  is  the 
same  thing  as,  an  overloaded  stomach ;  and  there  can  be  no  doubt  that 
artificial  mastication  becomes  a  snare  when  it  leads  any  one  to  introduce 
a  large  quantity  of  finely-minced  meat  suddenly  and  rapidly  into  an 
unprepared  stomach,  especially  into  the  feeble  stomach  of  an  invalid, 
under  the  idea  that,  because  the  meat  is  so  nicely  minced,  and  so  very 
tender,  it  can  be  no  possible  burden  to  that  sorely-tried  organ.  Natural 
mastication  has,  besides,  another  advantage  over  the  artificial  process, 
which  is  perhaps  not  always  recognized.  Whenever  food  enters  the 
mouth,  it  gives  rise  to  what  is  called  a  flow  of  saliva.  This  saliva  is 
secreted  by  certain  glands,  which  pour  into  the  mouth  the  fluid  they 
strain  off  from  the  blood,  and  which  are  excited  or  stimulated  to  action 
by  the  presence  of  food  in  the  mouth,  as  well  as  by  other  causes.  Saliva 
rapidly  changes  starch  into  sugar,  and  sugar  is  pre-eminently  a  soluble 
body,  passing  with  the  greatest  ease  from  the  alimentary  canal  into  the 
blood."  —  People's  Magazine  (London). 

3.  Experiment.      Saliva.  —  The  chemical  action  of  saliva  upon  boiled 
starch  may  be  demonstrated  by  the  following  simple  experiments : 

1.  Prepare  a  thin  solution  of  boiled  starch ;  three  parts  of  starch  to 
one  hundred  parts  of  water ;  boil  for  a  few  minutes. 


W.  Its  final  importance  ?    Starch?    How  effected?    Ptyaliu? 


DIGESTION  127 

21.  Importance  of  Mastication   and  Insalivation. — Each,  of 
these  processes  complements  the  other,  and  makes  the  entire 
work  available;  for,  by  their  joint  action,  they  prepare  the 
food  in  the  best  possible  manner  for  further  digestive  changes. 
The  study  of  these  preliminary  functions  will  appear  the  more 
important,  when  we  reflect  that  they  are  the  only  ones  which 
we  can  regulate  by  the  will.    For,  as  soon  as  the  act  of  swallow- 
ing begins,  the  food  not .  only  passes  out  of  sight,  but  beyond 
control;  and  the  subsequent  acts  of  digestion  are  consequently 
involuntary  and  unconsciously  performed. 

22.  'It  is  generally  known  that  rapid  eating  interferes  with 
digestion.     How  does  this  occur  ?     In  the  first  place,  in  rapid 
eating,  the  flow  of  the  saliva  is  insufficient  to  moisten  the  solid 
parts  of  the  food,  so  that  they  remain  too  hard  and  dry  to  be 
easily  swallowed.     This  leads  to  the  free  and  frequent  use  of 
water,  or  some  other  beverage,  at  meals,  to  "wash  down"  the 
food  —  a  most  pernicious  practice.     For  these  fluids  not  only 

2.  Obtain  a  fresh  quantity  of  saliva,  which  is  best  done  by  revolving 
a  small  pebble  in  the  mouth,  which  causes  a  copious  flow.     Collect  this 
iii  a  separate  vessel. 

3.  Demonstrate  that  no  sugar  is   present  in  this  starch  solution. 
Obtain  from  a  druggist  an  ounce  or  two  of  "Fehling's  solution"  (this 
is  a  solution  of  sulphate  of  copper  and  of  certain  alkalies).     Sugar  has 
the  power  of  changing  the  sulphate  into  an  oxide  of  copper  which  is  red- 
dish-brown.    Of  this  put  half  a  teaspoonful  into  a  test-tube,  add  an  equal 
quantity  of  the  starch  solution,  and  let  it  come  to  a  boil  over  an  alcohol 
lamp.    No  change  in  the  blue  color  will  be  observed. 

4.  Demonstrate  that  the  saliva  does  not  contain  sugar  by  boiling  a 
small  quantity  with  an  equal  quantity  of  "Fehling's  solution,"  when  no 
change  of  the  blue  color  will  be  observed. 

5.  Now  in  a  third  test-tube  mix  a  quantity  of  the  starch  solution  with 
one-third  its  volume  of  fresh  saliva,  and  set  aside  for  five  to  ten  minutes 
in  a  warm  place,  or  a  glass  of  warm  water  of  about  100°  F.     Then  take 
of  this  again  a  small  quantity  and  add  an  equal  part  of  "Fehling's  solu- 
tion," shake  the  mixture  and  boil.     As  soon  as  the  boiling  point  is 
approached,  it  will  be  seen  that  the  blue  color  disappears,  being  replaced 
by  a  reddish-brown  color.     This  demonstrates  the  presence  of  sugar  in 
the  starch  solution,  produced  by  the  action  of  the  saliva  added. 


21.  Each  of  the  processes  ?    Why  ia  a  knowledge  of  the  digestive  functions  important  ? 
How  shown  ? 

22.  Kapid  eating?   Describe  the  process  and  effects. 


128  DIGESTION 

cannot  take  the  place  of  the  natural  digestive  juices,  but,  on 
the  contrary,  dilute  and  weaken  them. 

23.  Secondly,  the  saliva  being  largely  the  medium  of  the 
sense  of  taste,  the  natural  flavors  of  the  food  are  not  devel- 
oped,  and    consequently   it    appears    comparatively    insipid. 
Hence    the    desire    for    highly-seasoned    food,    and    pungent 
sauces,  that  both  deprave  the  taste  and  over-excite  the  diges- 
tive organs.     Rapid  eating  also  permits  the  entrance  of  injuri- 
ous substances  which  may  escape  detection  by  the  taste,  and 
be  unconsciously  received  into  the  system.     In  some  instances, 
the  most  acrid  and  poisonous  substances  have  been  swallowed 
"  by  mistake,"  before  the  sense  of  taste  could  act  and  demand 
their  rejection. 

24.  Thirdly,  the  food,  being  imperfectly  broken  up  by  the 
teeth,  is  hurried  onward  to  the  stomach,  to  be  by  it  more 
thoroughly  divided.     But  the  stomach  is  not  at  all  adapted  to 
perform  the  task  thus  imposed  upon  it ;  and  the  crude  masses 
of  food  remain  a  heavy  burden  within  the  stomach,  and  a 
source  of  distress  to  that  organ,  retarding  the  performance 
of  its  proper  duty.     Hence  persons  who  habitually  eat  too 
rapidly,  frequently  fall  victims  to  dyspepsia.*     Kapid  eating 
also   conduces   to   overeating.      The    food    is    introduced    so 
rapidly  that  the  system  has  not  time  to  recognize  that  its 
real  wants  are  met,  and  hence  the  appetite  continues,  although 
more  nutriment  has  been  swallowed  than  the  system  requires, 
or  can  healthfully  appropriate. 

25.  The  Stomach.  —  As  soon  as  each  separate  portion  of  food 
is  masticated  and  insalivated,  it  is  swallowed;  that  is,  it  is 
caused  to  move  downward  to  the  stomach,  through  a  narrow 
muscular  tube  about  nine  inches  in  length,  called  the  oesopJia- 
gusj  or  gullet  (Fig.  29).     The  stomach  is  the  only  large  expan- 

*  For  the  same  reason,  persons  who  prematurely  lose  their  teeth  suffer 
from  dyspepsia.  For  them  a  proper  means  of  relief  is  the  use  of  artificial 
teeth. 

28.   Loss  of  taste  ?    Another  effect  of  rapid  eating  ?    Mistakes  ? 

24.  Effect  of  imperfectly -broken  food  in  the  stjomach  ?    Dyspepsia  ?    Overeating  ? 

25.  Gullet  ?    Describe  the  stomach  and  its  location.    Effects  of  gormandizing  ? 


DIGESTION 


129 


sion  of  the  digestive  canal,  and  is   a  most  important  organ 
of    digestion.      It  is   a   hollow,  pear-shaped    pouch,    having 

a  capacity  of  three  pints, 
in  the  adult.  Its  walls 
are  thin  and  yielding,  and 
may  become  unnaturally 
distended,  as  in  the  case 
of  those  who  subsist  on 
a  bulky,  innutritions  diet, 
and  of  those  who  habit- 
ually gormandize. 

26.  The  stomach  has 
also  two  openings;  that 
by  which  food  enters, 
being  situated  near  the 
heart,  is  called  the  car- 
diac, or  heart  orifice ;  the 
other  is  the  pylorus,  or 
"gatekeeper,"  which 
guards  the  entrance  to  the 
intestines,  and,  under  ordi- 
nary circumstances,  per- 
mits only  such  matters  to 
pass  it  as  have  first  been 
properly  acted  upon  in  the 
stomach.  Oojp^  buttons,  and  the  like  are,  however,  readily 
allowed  to  pass,  because  they  can  be  of  no  use  if  retained. 
The  soft  and  yielding  texture  of  this  organ  —  the  stomach  — 
indicates  that  it  is  not  designed  to  crush  and  break  up  solid 
articles  of  food. 

27.  The  Gastric  Juice.  —  We  have  seen  how  the  presence  of 
food  in  the  mouth  excites  the  salivary  glands,  quickly  causing 
the  saliva  to  flow.  In  the  same  manner,  when  food  reaches 
the  stomach,  its  inner  lining,  the  mucous  membrane,  is  at 

26.  Heart  orifice?    Gatekeeper?    Coins,  etc.  ?    Indication  of  the  soft  and  yielding  text- 
ure  of  the  stomach  ? 

27.  What  is  meant  by  the  gastric  juice  ? 


FIG.  28.  — SECTION  OF  CHEST  AND  ABDOMEN 

A,  Heart  E,  Gall  Bladder 

B,  The  Lungs  F,  Stomach 

C,  Diaphragm  G,  Small  Intestine 

D,  The  Liver  H,  Large  Intestine 


130 


DIGESTION 


once  excited  to  activity.  At  first,  'its  surface,  which  while 
the  stomach  is  empty  presents  a 
pale  pink  hue,  turns  to  a  bright  red 
color,  for  the  minute  blood-vessels 
which  course  through  it  are  filled 
with  blood.  Presently  a  clear,  color- 
less, and  acid  fluid  exudes,  drop  by 
drop,  from  millions  of  little  tubes  in 
the  inner  surface  of  the  stomach, 
until  finally- the  surface  is  moistened 
in  every  part,  and  the  fluid  begins  to 
mingle  with  the  food.  This  fluid  is 
termed  the  gastric  juice. 

28.  The  gastric  juice  dissolves  cer- 
tain articles  of  food,  especially  those 
belonging  to  the  albuminoid  class. 
This  solvent  power  is  due  to  its 
peculiar  ingredient,  pepsin;  in  diges- 
tion, this  substance  acts  like  a  fer- 
ment —  that  is,  it  induces  changes  in 
the  food  simply  by  its  presence,  but 
does  not  itself  undergo  change.  The 
acidity  of  the  gastric  juice,  which  is 
due  to  hydrochloric  acid,  is  not  acci- 
dental; for  we  find  that  the  pepsin 
cannot  act  in  an  alkaline  solution  — 
that  is,  one  which  is  not  acid  or  neu- 
tral. The  quantity  of  gastric  juice 
secreted  daily  is  very  large,  probably 

not  less   than   three   Or   four   pints   at    FIG.  29.  ALIMENTARY  CANAL— in- 
,  ,        r_,  i      ,1  •       n     •  -i    •  eluding   Gullet,   Stomach,   Small 

each    meal.       Though    thlS   fluid   IS    at       and  Large  Intestines 

once  used  in  the  digestion   of   the 

food,  it  is  not  lost ;  since  it  is  soon  re-absorbed  by  the  stomach, 
together  with  those  parts  of  the  food  which  it  has  digested  and 
holds  in  solution. 


28.   What  is  the  office  of  the  gastric  juice  ?    Acidity  of  the  gastric  juice  2    Quantity  of 
gastric  juice  used  ?    What  becomes  of  it  ? 


DIGESTION  131 

29.  Movements  of  the  Stomach.  —  The  inner  coating  of  the 
stomach  is  the  mucous  membrane,  which,  as  we  have   seen, 
furnishes  the  gastric  juice.     Next  to  this  coating  lies  another, 
called  the  muscular  coat,  composed  of  involuntary  muscular 
fibres,  some  of  which  run  circularly,  and  others  in  a  longitudinal 
direction.    These  expand  to  accommodate  the  food  as  it  is  intro- 
duced, and  contract  as  it  passes  out.     In  addition,  these  fibres 
are  in  continual  motion  while  food  remains  in  the  stomach, 
and  they  act  in  such  manner  that  the  contents   are   gently 
turned  round  from  side  to  side,  or  from  one  end  of  it  to  the 
other. 

30.  By  these  incessant  movements  of  the  stomach,  called 
the  peristaltic  movements,  the  gastric  juice  comes  in  contact 
with  all  parts  of  the  food.     We  are,  however,  not  conscious 
that  these  movements  take  place,  nor  have  we  the  power  to 
control  them.     When  such  portions  of  the  food  as  are  suffi- 
ciently digested  approach  the  pylorus,  it  expands  to  allow  them 
to  pass  out,  and  it  closes  again  to  confine  the  residue  for  further 
preparation. 

31 .  The  knowledge  of  these  and  other  interesting  and  instruc- 
tive facts  has  been  obtained  by  actual  observation ; '  the  work- 
ings of  the  stomach  of  a  living  human  being  have  been  laid 
open  to  view  and  examined  —  the  result  of  a  remarkable  acci- 
dent.    Alexis  St.  Martin,  a  Canadian  voyageur,  received  a  gun- 
shot wound  which  laid  open  his  stomach,  and  which,  in  healing, 
left  a  permanent  orifice  nearly  an  inch  in  diameter.     Through 
this  opening  the  observer  could  watch  the  progress  of  digestion, 
and  experiment  with  different  articles   of  food.     Since  that 
occurrence,  artificial  openings  into  the  stomach  of  the  inferior 
animals  have  been  repeatedly  made,  so  that  the  facts  of  stomach- 
digestion  are  very  well  ascertained  and  verified.     (Bead  Note  4. ) 

4.   The  Digestibility  of  Solid  Foods. —  "The  accompanying  table 
shows  some  of  the  results  obtained  from  the  experiments  of  Dr.  Beaumont 


29.  Muscular  coat  of  the  stomach  ?  Expansion  and  contraction  of  its  fibres  ?  Action 
of  the  fibres  ? 

80.  Peristaltic  movements  ?  What  is  said  of  our  consciousness  of  and  power  over  these 
movements  ?  Describe  the  movement  of  the  pylorus. 

31.  How  has  the  knowledge  and  the  workings  of  the  stomach  been  ascertained  ?  St. 
Martin  ?  How  else  ?  ^..j  L  fr  ^  ^ 

Of  T  H  f 


132 


DIGESTION- 


32.  Gastric  Digestion.  —  What  portions  of  the  food  are 
digested  in  the  stomach  ?  It  was  formerly  thought  that  all 
the  great  changes  of  digestion,  were  wrought  here,  but  later 
investigation  has  taught  us  better.  We  now  know  that  the 
first  change  in. digestion  takes  place  in  the  mouth,  by  the  partial 
conversion  of  starch  into  sugar.  We  also  know  that,  of  the'-' 
three  organic  food  principles  (considered  in  Chap.  IV.)  two 
—  the  fats  and  the  sugars, —  are  but  slightly  affected  by  the 
stomach ;  but  that  its  action  is  confined  to  that  third  and  very 
important  class  from  which  the  flesh  is  formed,  the  albuminoids. 
A  few  articles  need  no  preparation  before  entering  the  system, 
as  water,  salt,  and  fruit-sugar.  These  are  rapidly  taken  up 
by  the  blood-vessels  of  the  stomach,  which  everywhere  underlie 
its  mucous  membrane  in  an  intricate  and  most  delicate  network. 
In  this  way  the  function  of  absorption  begins. 


upon  the  stomach  of  Alexis  St.  Martin.  It  will  surprise  many  to  find  that 
vegetable  foods  —  they  are  placed  in  the  latter  part  of  the  table  —  require 
so  long  a  time  for  their  digestion." 


Food. 


Time  re- 
Mode  of   quired  for 
Cooking,   digestion, 
h.  in. 

Pork roasted  .....5  15 

Cartilage boiled 4  15 

Ducks roasted 4  0 

Fowls do 40 

Do boiled 4  0 

Beef fried 4  0 

Eggs do 3  30 

Do hard  boiled. .3  30 

...3  30 


Oysters stewed 3  30 

Mutton roasted 3  15 

Do boiled 3    0 

Beef roasted 3    0 

Do boiled 2  45 

Chicken fricasseed  . .  .2  45 

Lamb broiled 2  30 

Pig  (suckling) roasted 2  80 

Goose do 2  30 

Gelatin boiled 2  30 

Turkey do 225 

Eggs roasted 215 

Cod  Fish  (cured,  dry) ....  boiled 2    0 

Ox  Liver broiled 2    0 

Venison  Steak do 180 


Food. 


Mode  of 
Cooking. 


Salmon  Trout boiled . . 

Eggs  (whipped) raw 

Tripe  (soused) boiled . . 

Pig's  Feet  (soused) do.    .. 

Cabbage .-. boiled. . 

Beetroot do.    .. 

Turnips do.    . . 

Potatoes do.    .. 

Wheaten  Bread baked . . 

Carrots 

Indian  Corn  Bread 

Do.         Cake. 

Apple-dumpling  .. 

Potatoes 

Do roasted 

Parsnips boiled. . 

Sponge  Cake baked . . 

Beans boiled.. 

Apples  (sour) raw. . . . 

Barley boiled. . 

Tapioca do.   . . 

Sago  do.    .. 

Apples  (sweet) raw 

Rice boiled.. 


...boiled.. 
...baked.. 
...  do.  .. 
...boiled.. 
...baked.. 


Time  re- 
quired for 
digestion, 
h.  m. 

1  80 

1  80 

1    0 

1    0 

4    0 

3  45 

3  30 

.  ...~.C  30 

3  30 

3  15 

3  15 

3    0 

3    0 

2  33 

2  30 

.....2  30 

2  30 

2  30 

2    0 

2    0 

2    0 

1  45 

1  30 

...1    0 


82.  What  was  formerly  thought  ?     What  do  we  now  know  ? 
know  ?    Water,  salt,  and  sugar  ?    Absorption  ? 


What  else  do  we  now 


DIGESTION  133 

33.  The  albuminoid  substances  are  speedily  attacked  and 
digested  by  the  gastric  juice.  From  whatever  source  they  are 
derived,  vegetable  or  animal,  they  are  all  transformed  into  the 
same  digestive  product,  called  peptone.  This  is  very  soluble 
in  water,  and  is  in  part  absorbed  by  the  blood-vessels  of  the 
stomach.  After  a  longer  or  shorter  time,  varying  from  one  to 
five  hours,  according  to  the  individual  and  the  quantity  and 
quality  of  his  food,  the  stomach  will  be  found  empty.  Kot 
only  the  unabsorbed  digested  food,  but  also  those  substances 
which  the  stomach  could  not  digest,  have  passed  little  by  little 
through  the  pylorus,  to  undergo  further  action  in  the  intestines. 
At  the  time  of  its  exit  the  digested  food  is  of  a  pulpy  con- 
sistence, and  dark  color,  and  is  then  known  as  the  cliyme.^ 
(Head  Notes  5  and  6.) 

5.  Indigestible  Matters.  —  "Children  sometimes  swallow  coins,  but- 
tons, etc., and  so  cause  great  alarm.     There  is  little  real  ground  for  appre- 
hension under  these  circumstances,  unless  the  coins  are  bronze.     If  the 
latter,  there  is  some  cause  for  fear  that  copper  poisoning  will  ensue,  and 
the  ready  passage  of  the  coin  is  desirable.     This  is  best  effected  by  meals 
of  figs  or  pudding,  in  which  the  coins  are  imbedded,  and  so  passed  harm- 
lessly.    As  to  bulk,  whatever  will  go  into  the  stomach  will  pass  the 
various  straits  and  emerge  again."  —  Fothergill. 

6.  Experiment.    Gastric  Juice.  — The  action  of  the  gastric  juice  upon 
the  albuminoids  can  be  readily  demonstrated  outside  of  the  body.     For 
this  it  is  necessary  to  prepare  a  solution  of  pepsin  and  a  solution  of  hydro- 
chloric acid.     The  first  of  these  may  be  made  in  one  of  two  ways.    The 
simplest  of  these  is  to  obtain  some  pure  pepsin  from  the  druggist,  and 
dissolve  of  this  thirty  grains  in  four  ounces  of  pure  glycerin ;  the  other, 
but  more  complicated  way,  is  to  obtain  a  pig's  stomach,  dissect  off  the 
mucous  membrane,  mince  finely  and  add  six  ounces  of  glycerin,  set  aside 
for  a  week  and  strain  through  muslin.     The  solution  of  hydrochloric  acid 
should  be  of  the  strength  of  two  parts  per  thousand,  which  would  be 
about  two  or  three  drops  of  the  strong  acid  to  four  ounces  of  water. 

Demonstrate  that  neither  the  solution  of  pepsin  nor  the  hydrochloric 
acid  alone  have  the  power  to  digest  albuminoids. 
Prepare  three  test-tubes  as  follows  : 

1.  Into  one  put  about  a  teaspoonful  of  the  pepsin  solution,  and  add  a 
small  piece  of  the  white  of  a  hard-boiled  egg. 

2.  Into  the  second  test-tube  put  a  teaspoonful  of  the  dilute  hydro- 
chloric acid,  and  add  again  a  small  piece  of  the  white  of  the  egg. 

3.  The  third  test-tube  fill  half  with  the  solution  of  acid,  add  half  a  tea- 
spoonful  of  the  pepsin  solution,  and  again  a  small  piece  of  the  egg. 

83.  Albuminose?    The  process? 


134  DIGESTION 

34.  The  Intestines.  —  The  intestines  are  continuous  with  the 
stomach,  and  consist  of  a  fleshy  tube,  or  canal,  twenty-five  feet 
in  length.     The  small  intestine,  whose  diameter  is  about  one 
inch  and  a  half,  is  twenty  feet  long,  and  very  winding.     The 
large  intestine  is  much  wider  than  the  former,  and  five  feet 
long  (Fig.  29).    The  general  structure  of  these  organs  resembles 
that  of  the  stomach.    Like  it,  they  are  provided  with  a  mucous 
membrane,  or  inner  lining,  whence  flow  their  digestive  juices ; 
and,  just  outside  of  this,  a  muscular  coat,  which  propels  the 
food  onward  from  one  point  to  another. 

35.  Moreover,  both  the  intestines  and  stomach  are  enveloped 
in  the  folds  of  the  same  outer  tunic  or  membrane,  called  the 
peritoneum.     This  is  so  smooth  and  so  well  lubricated,  that 
the   intestines    have   the   utmost   freedom   of  motion   within 
the  abdomen.     In  the  small  intestines  the  work  of  digestion  is 
completed,  the  large  intestine  receiving  from  them  the  indi- 
gestible residue  of  the  food,  and  in  time  expelling  it  from  the 
body. 

36.  Intestinal  Digestion. — As  soon  as  the  food  passes  the 
pylorus  and  begins  to  accumulate  in  the  upper   part   of  the 
intestines,  it  excites  the  florw  of  a  new  digestive  fluid,  which 
enters  through  a  small  tube,  or  duct,  about  three  inches  below 
the  stomach.     It  is  formed  by  the  union  of  two  distinct  fluids 
—  the  bile  and  the  pancreatic  juice.     The  bile  is  secreted  by  the 
cells  of  the  liver,  the  largest  gland  of  the  body,  situated  on 
the  right  side  and  upper  part  of  the  abdomen  (Fig.  28).     The 
bile  is  constantly  formed,  but  it  flows  most  rapidly  during 
digestion.    During  the  intervals  of  digestion  it  is  stored  in  the 
gall-bladder,  a  small  membranous  bag  attached  to  the  under 


Now  set  these  three  tubes  aside  in  a  warm  place  for  a  few  hours,  or 
until  the  following  day,  when  you  will  be  able  to  demonstrate  that  in  the 
first  two  no  change  has  taken  place,  while  the  white  of  egg  in  the  third 
has  been  entirely  dissolved: 


34.  What  are  the  intestines?    The  small  intestines?    The  large  intestines  I    Their 
structure  ? 

85.  Peritoneum?    The  work  of  digestion  ? 

86.  The  presence  of  food  in  the  intestines  ?    Bile  2 


DIGESTION  135 

side  of  the  liver.  This  fluid  is  of  a  greenish-yellow  color,  hav- 
ing a  peculiar  smell,  and  a  very  bitter  taste ;  its  exact  part  in 
the  process  of  digestion  is  not  known.  That  it  is  an  impor- 
tant one,  cannot  be  doubted.  For  if  its  proper  flow  into  the 
intestinal  canal  is  interfered  with,  or  stopped,  serious  illness 
is  the  result.  Its  chief  function  seems  to  be  to  aid  in  the 
digestion  of  fats,  by  emulsifying  them ;  it  also  acts  as  a  disin- 
fectant of  the  intestinal  tract,  increases  the  muscular  contrac- 
tions of  the  intestines,  and  aids  in  a  general  way,  in  the 
absorption  of  the  products  of  digestion.  (Read  Note  7.) 

37.  The  pancreatic  juice  is  the  product  of  a  gland  called  the 
pancreas,  situated  behind  the  stomach.    This  fluid  is  colorless, 
watery,  alkaline,  and  without  odor.      Like  the  digestive  juices 
previously  described,  it  owes  its  solvent  power  to  its  peculiar 
ferments.     The  most  important  of  these  ferments,  called  pan- 
creatin,  transforms  starch  into  sugar.     Another,  trypsin,  causes 
the  solution  of  uudissolved  albuminoid  substances ;  and  a  third 
ferment,  which  has  not  received  a  name,  causes  a  partial  acidi- 
fication of  the  fats.     By  the  joint  action  of  these  fluids,  the 
food  is  prepared  for  absorption.    There  results  from  this  action 
of  the  pancreatic  juice  a  white  and  milky  fluid,  termed  the 
chyle,  which  holds  in  solution  the  digestible   portions  of  the 
food,  and  is  spread  over  the  extensive  absorbent  surface  of 
the  small  intestines.'    (Read  Note  8.) 

38.  The  mucous  membrane  of  the  intestines,  also,  secretes 

7.  Experiment.  Bile.  — The  chief  function  of  the  bile  in  the  diges- 
tion of  food  is  the  emulsifying  of  fats. 

If  a  quantity  of  oil  is  shaken  up  with  an 'equal  part  of  water  in  a  test- 
tube,  the  two  will  not  mix.  But  if  we  substitute  bile  for  the  water,  and 
shake  thoroughly,  we  obtain  an  emulsion  which  will  separate  but  slowly 
and  imperfectly. 

The  bile  may  be  obtained  from  the  gall-bladder  of  the  ox  or  sheep  at 
any  butcher's  or  slaughter-house. 


37.   What  produces  the  pancreatic  juice  ? 
Where  is  the  pancreas  situated  ? 
Describe  pancreatin.    Trypsin. 
How  is  food  prepared  for  absorption  f 
What  is  chyle  ?    What  is  its  function  ? 
How  performed  ? 


136  DIGESTION 

or  produces  a  digestive  fluid  by  means  of  numerous  "  follicles," 
or  minute  glands;  this  is  called  the  intestinal  juice.  From 
experiments  on  the  lower  animals,  it  has  been  ascertained  that 
this  fluid  exerts  a  solvent  influence  over  each  of  the  three 
organic  food  principles,  and  in  this  way  completes  the  action 
of  the  fluids  previously  mentioned,  viz. :  of  the  saliva  in 
converting  starch  into  sugar,  of  the  gastric  juice  in  digesting 
the  albuminoids,  and  of  the  pancreatic  juice  and  bile  in 
emulsifying  the  fats. 

39.  The  Large   Intestine   (or  Colon)  is  joined  to  the  small 
intestine  at  right  angles  to  it,  at  some  distance  from  its  closed 
lower  end.     At  this  point  of  junction  there  is  a  valve,  called 
the  ileo-ccecal  valve,  which  prevents  the  contents  of  the  small 
intestine  from  passing  back  into  the  latter  after  they  have  once 
entered  the  large  intestine.     The  closed  lower  end  of  the  large 
intestine  (called  the  caecum)  ends  in  a  slender  tube  from  two  to 
five  inches  in  length,  called  the  vermiform  appendix,  inflam- 
mation of  which  produces  the  disease  known  as  appendicitis. 
From  its  beginning,  the  large  intestine  passes  upward  to  the 
under  surface  of  the  liver,  this  portion  being  called  the  ascend- 
ing colon ;  then  it  turns  at  right  angles  to  the  left,  and  across 
the  abdominal  cavity  just  below  the  stomach,  until  it  reaches 
the  left  side  of  the  abdomen,  this  portion  being  called  the 
transverse  colon ;  from  here  it  passes  downward,  forming  the 
rectum. 

40.  Absorption.  —  With  the  preparation  of  the  chyle,  the 
work  of  digestion  is  completed;  but  it  has  not  yet  become  a 
part  of  the  blood,  by  means  of  which  it  is  to  reach  the  dif- 
ferent parts  of  the  body.     The  process  by  which  the  liquefied 
food  passes  out  of  the  alimentary  canal  into  the  blood  is  called 
absorption.     This  is  accomplished  in  two  ways :  first,  by  the 


38.  What  does  the  mucous  membrane  of  the  intestines  secrete  ?    What  is  it  called  ? 
What  influence  does  this  fluid  exert  ?    The  action  of  what  other  fluids  is  completed  by  the 
intestinal  juice  ? 

39.  Where  is  the  large  intestine  joined  to  the  small  intestine  ?    Where  is  the  ileo-csecal 
valve  ?    What  purpose  does  it  serve  ?    What  is  the  vermiform  appendix  ?    What  disease  is 
produced  by  inflammation  of  the  vermiform  appendix  ?    Describe  the  course  of  the  large 
intestine. 


DIGESTION  137 

blood-vessel*.  We  have  seen  how  the  inner  membrane  of  the 
stomach  is  underlaid  by  a  tracery  of  minute  and  numerous 
vessels,  and  how  some  portions  of  the  food  are  by  them 
absorbed.  The  supply  of  blood-vessels  to  the  intestines  is 
even  greater;  particularly  to  the  small  intestines,  .where  the 
work  of  absorption  is  most  actively  carried  on. 

41.  The  absorbing  surface  of  the  small  intestines,  if  con- 
sidered as  a  plane  surface,  amounts  to  not  less  than  half  a 
square  yard.  Besides,  tSe  mucous  membrane  is  formed  in 
folds  with  an  immense  number  of  thread-like  prolongations, 
called  v #//,'•  which  indefinitely  multiply  its  absorbing  capacity. 
These  villi  give  the  surface  the  appearance  and  smoothness  of 
velvet,  and  during  digestion  they  dip  into  the  canal,  and,  by 


8.  Experiment.  Pancreatic  Juice.  — To  obtain  the  pancreatic  juice, 
it  will  be  necessary  to  extract  it  from  a  fresh  pancreas,  "  sweet-bread  " 
(which  may  be  bought  of  any  butcher),  by  means  of  either  water  or 
glycerin.  -Mince  the  pancreas  finely  and  add  sufficient  of  either  of  these 
liquids  to  cover  it,  set  aside  for  a  day  and  strain  or  filter.  The  glycerin 
extract  will  keep  for  a  long  time  ;  the  watery  extract  soon  spoils. 

The  pancreatic  juice  has  a -digestive  action  on  all  the  food-stuffs. 

Its  action  upon  boiled  starch  may  be  demonstrated  by  repeating  the 
experiments  detailed  under  "  Saliva,"  only  substituting  the  extract  of  the 
pancreas  for  the  saliva. 

Its  action  upon  albuminoids  is  shown  by  adding  to  a  few  teaspoonfuls 
of  the  pancreatic  extract  some  finely  minced  meat,  or  a  part  of  the 
white  of  a  boiled  egg.  But  as  the  action  of  the  pancreatic  juice  can 
only  proceed  in  an  alkaline  medium,  it  is  necessary  to  be  certain  of  the 
alkalinity  of  the  fluid.  This  is  be.st  done  by  adding  about  five  grains  of 
carbonate  of  soda  (washing  soda)  to  each  ounce  of  pancreatic  extract. 
Set  the  test-tube  aside  in  a  warm  place  for  a  few  hours,  when  the  meat 
or  white  of  egg  will  be  found  entirely  dissolved. 

Its  action  upon  fats  may  be  shown  by  shaking  up  in  a  test-tube  a 
quantity  of  the  extract  with  an  equal  part  of  melted  lard  or  oil,  when 
we  will  obtain  a  very  perfect  emulsion. 


40.  What  completes  the  work  ofdisrestion  ?    How  much  thus  far  has  been  done  with  the 
food?    What  remains  to  be  done*    What  is  this  process  called?    In  what  two  ways  is  it 
accomplished  ?     By  what  is  the  inner  membrane  of  the  stomach  underlaid  ?     What  purpose 
does  it  serve?    Are  the  intestines  supplied  with  corresponding  blood-vessels?    In  greater 
or  less  quantity  ?     Where  is  the  work  of  absorption  most  actively  carried  on  ? 

41.  Considered  as  a  plane  surface,  what  is  the. extent  of  the  absorbing  surface  of  the 
small  intestines?    Describe  the  formation  of  the  mucous  membrane.     What  are  the  villi  ? 
In  what  way  do  the,  villi  affect  the  surface  of  the  membrane?    What  is  their  office  during 
digestion  ? 


138 


DIGESTION 


means  of  their  blood-vessels,  absorb  its  fluid  contents,  just  as 
the  spongioles  which  terminate  the  rootlets  of  plants  imbibe 
moisture  from  the  surrounding  soil. 

42.  Secondly,  absorption  is  also  effected  by  the  lacteals,  a 
set  of  vessels  peculiar  to  the  small  intestines.  These  have 
their  beginnings  in  the  little  villi  just  mentioned,  side  by  side 
with  the  blood-vessels.  These  two  sets  of  absorbents  run  in 


D         B 

FIG.  30. —THE  LACTEALS 
A,  Small  Intestine;  B,  Lacteals;  C,  Thorax  Duct;  D,  Absorbents;  E,  ^iood-vessel 


different  courses,  but  their  destination  is  the  same,  which  is 
the  right  side  of  the  heart.  The  lacteals  receive  their  name 
from  the  milky-white  appearance.  After  a  meal  containing 
a  portion  of  fat,  they  are  distended  with  chyle,  which  they 


42.  How  is  absorption  effected  in  another  way  ?    Describe  it. 
From  what  is  the  name  of  the  lacteals  derived  ? 
What  tube  is  formed  by  the  union  of  the  lacteals  ?     . 
Describe  its  courst. 


DIGESTION  139 

are  specially  adapted  to  receive;  at  other  times  they  are 
hardly  discernible.  The  lacteals  all  unite  to  form  one  tube, 
the  thoracic  duct,  which  passes  upward  through  the  thorax, 
or  chest,  and  empties  into  a  large  vein,  situated  just  beneath 
the  left  collar-bone. 

43.  The  Absorbents.  —  The  lacteals  belong  to  a  class  of  ves- 
sels known  as  absorbents,  or  lymphatics,  which  exist  in  nearly 
all  parts  of  the  body,  except  the  brain  and  spinal  chord.     The 
fluid  which  circulates  through  the  lymphatics  of  the  limbs, 
and  all  the  organs  not  concerned  in  digestion,  is  called  lymph. 
This  fluid  is  clear  and  colorless,  like  water,  and  thus  differs 
from  the  milky  chyle  which  the  lacteals  carry  after  digestion : 
it  consists  chiefly  of  the  watery  part  of  the  blood,  which  was 
not  required  by  the  tissues,  and  is  returned  to  the  blood  by 
the  absorbents  or  lymphatics.  -  (Read  Note  9.) 

44.  Osmosis  is  the  name  given  to  that  process  which  enables 
two  fluids,  capable  of  being  mixed,  to  pass  through  animal 
membrane,  which  separates  them.     This  may  be  readily  illus- 
trated by  filling  a  glass  tube  half  full  with  a  strong  salt  solu- 
tion, and  closing  its  open  end  by  a  piece  of  bladder  or  intestine, 
and  then  standing  the  tube,  with  the  membrane  downward,  in 
a  glass  of  water.    After  a  while  it  will  be  noticed  that  the  sur- 
rounding fresh  water  has  become  salty,  and  also  that  the  fluid 
in  the  glass  tube  has  increased  in  volume.    Upon  analyzing  the 
two  fluids  now,  we  will  find  that  more  water  has  passed  into 
the  salt  solution  than  salt  into  the  water,  showing  that  the 
lighter  fluid  (water)  passes  more  readily  into  the  denser  fluid 
(salt  solution).      The   more   abundant   passage  of  the  water 
through  the  membrane  to  the  salt  is  called  endosmosis;  and  the 


48.   To  what  class  of  vessels  do  the  lacteals  belong  ? 

In  what  parts  of  the  body  are  absorbents  not  found  ? 

What  fluid  circulates  through  the  lymphatics  of  the  limbs  ? 

In  what  respect  does  it  differ  from  the  chyle  carried  by  the  lacteals  after  digestion  ? 

Of  what  does  it  consist? 

How  is  it  returned  to  the  blood  ? 
44.  Describe  the  process  of  osmosis. 

How  may  it  be  illustrated  ? 

Describe  the  experiment. 

What  is  endosmosis  ?    Exosmosis  ? 


140  DIGESTION 

more   scanty  passage  of  the  salt  outward  into  the  water  is 
called  exosmosis.     (Read  Note  9.) 

45.  Dialysis.  —  Different   substances  will   penetrate  animal 
membrane  with  different  degrees  of  rapidity.     As  a  rule,  crys- 
tallizable  substances,  such  as  mineral  salts,  glucose,  or  urea, 
pass  with  facility ;  while  non-crystallizable,  such  as  albumen, 
starch,  or  gum,  pass  through  not  at  all,  or  with  difficulty.    The 
former   substances   are   called  diffusible,  and  the  latter  non- 
diffusible.     This  distinction  is  not  absolute,  however,  for  by 
increasing  the  pressure  on  one  side  of  the  membrane,  nearly 
all  soluble  substances  can  be  made  to  pass  through  to  some 
degree.     The  separation  of  substances  of  different  diffusibility 
from  each  other  is  called  dialysis.     To  illustrate :  If  a  mixture 
of  sugar  and  gum,  dissolved  in  water,  be  placed  on  one  side  of 
the  membrane,  and  pure  water  *  on  the  other,  it  will  be  found, 
that  the  sugar  will  pass  through  the  membrane,  while  the  gum 
will  be  left  behind.     It  is  by  this  process  of  dialysis  that  the 
products  of  digestion  are  separated  from  the  waste  and  indi- 
gestible parts  of  food,  and  absorbed  into  the  circulation. 

46.  The  absorption  of  the  food,  when  it  reaches  the  intes- 
tine in  liquefied  form,  is  as  follows :  all  of  it  passes  through  the 
epithelial  cells  of  the  villi  ^(see  Fig.  31),  and  thence  directly 
into  both  blood-vessels  and  lacteals ;  peptones,  water,  salts,  and 
glucose  pass  directly  into  the  vessels  and  lacteals,  and  emulsi- 
fied fats  after  passing  through  the  epithelial  cells  pass  into 
the  lacteals.     Peptones,  salts,  water,  and  fats  are  taken  from 
the  blood  by  the  tissues  directly,  while  the  glucose  is  carried 
through   the    portal  ^circulation   into   the   liver.     This   organ 
changes  the  glucose  to  a  new  substance,  called  glycogen,  and 
stores  it  up  in  its  interior,  to  remain  here  until  the  system 
needs  it;   when  the  tissues  require  glucose,  this  glycogen  is 
re-transformed    into    glucose,   and    passes    into    the    general 

45.  What  substances  easily  pass  through  animal  membrane  ?    What  are  these  substances 
called  ?    What  substances  pass  through  with  great  difficulty,  if  at  all  ?    What  are  they 
called  ?    Why  is  this  distinction  not  absolute  ?    What  is  dialysis  ?    Illustrate  the  process. 

46.  Describe  the  process  of  the  absorption  of  food,  after  it  has  reached  the  intestines  in 
liquefied  form.    What  substances  pass  directly  into  the  vessels  and  lacteals  ?    How  is  glu- 
cose modified  by  the  action  of  the  liver  ?    What  is  this  modified  substance  called  ? 


DIGESTION 


141 


circulation.      It  will  thus   be   seen  that    the    liver  plays   a 
very  important  part  in  the  process  of 
nutrition,  and  acts  as  a  storehouse  of 
food. 


47.  Circumstances  Affecting  Digestion. 
—  What  length  of  time  is  required  for 
the  digestion  of  food  ?  From  observa- 
tions made,  in  the  case  of  St..  Martin, 
the  Canadian  already  referred  to,  it  has 
been  ascertained  that,  at  the  end  of  two 
hours  after  a  meal,  the  stomach  is  ordi- 
narily empty.  How  much  time  is  needed 
to  complete  the  digestion  of  food,  within 
the  small  intestines,  is  not  certain ;  but 
from  what  we  have  learned  respecting 
their  methods  of  action,  it  must  be  evi- 
dent that  it  largely  depends  upon  the 
amount  of  starch  and  fat  which  the 
food  contains. 


FIG.  81.  —  Two  INTESTINAL 
VILLI.  MAGNIFIED  100  DI- 
AMETERS 

a,  6,  and  c,  Lacteals  ;  d,  Blood- 
vessels 


9.  Absorption  of  the  Lacteals.  —  "  The  force  by  which  the  milky  fluid 
moves  upward  through  the  lacteals  is  very  considerable.  This  has  been 
proved  by  the  distension  of  the  whole  system  of  vessels,  including  the 
thoracic  duct,  even  to  the  occurrence  of  rupture,  when  that  duct  has  been 
tied  in  an  animal  a  short  time  before  it  has  been  fed.  The  movement  of 
the  fluid  thus,  in  some  measure,  resembles  absorption  by  the  spongioles 
at  the  extremities  of  the  roots  of  trees,  and  the  continuous  rising  of  the 
sap.  The  thoracic  duct  may  become  diseased,  and  a  serious  derange- 
ment of  nutrition  take  place.  In  the  case  of  an  unfortunate  person, 
who  was  some  years  ago  exhibited  as  a  curiosity  under  the  name  of  the 
'living  skeleton,'  was  illustrated  the  slow  starvation  that  may  thus  be 
produced.  Although  he  was  able  to  take  food  in  abundant  supply,  he 
was  not  nourished  by  it.  Finally  he  died,  and  an  examination  of  his 
body  disclosed  the  fact  that  the  thoracic  duct  had  been  obstructed  by 
disease,  and  absorption  by  the  lacteals  was  prevented.  Hard  work 
directly  after  a  hearty  meal  is  bad  practice.  Remember  the  story  of  the 
two  hounds.  They  were  both  fed  alike  in  the  morning ;  one  of  them 
was  taken  out  to  run  on  a  hunt,  the  other  was  tied  up  at  home.  When 
the  master  came  back  from  the  hunt,  both  dogs  were  killed,  and  their 


41.  What  length  of  time  is  required  for  the  digestion  of  food} 


142  DIGESTION 

48.  In  addition  to  the  preparation  which  the  .food  undergoes 
in  cooking,  which  we  have  already  considered,  many  circum- 
stances affect  the  duration  of  digestion;  such  as  the  quality, 
quantity,  and  temperature  of  the  food;  the  condition  of  the 
mind   and   body;    sleep,   exercise,   and   habit.      Fresh   food, 
except  new  bread  and  the  flesh  of  animals  recently  slain,  is 
more  rapidly  digested  than  that  which  is  stale  ;  and  animal 
food  more  rapidly  than  that  from  the  vegetable  kingdom. 

49.  Food  should  not  be  taken  in  too  concentrated  a  form, 
the  action  of  the  stomach  being  favored  when  it  is  somewhat 
bulky ;  but  a  large  quantity  in  the  stomach,  especially  if  there 
is  much  liquid,  often  retards  digestion.     If  the  white  of  one 
egg  be  given  to  a  dog,  it  will  be  digested  in  an  hour,  but  if  the 
white  of  eight  eggs  be  given  it  will  not  disappear  in  four 
hours.     A  wine-glassful  of  ice-water  causes  the  temperature 
of  the  stomach  to  fall  thirty  degrees ;  and  it  requires  a  half- 
hour  before   it   will    recover   its   natural   warmth  —  about   a 
hundred  degrees  —  at  which  the  operations  of  digestion  are 
best  conducted.     A  variety  of  articles,  if  not  too  large  in 
amount,  is  more  easily  disposed  of  than  a  meal  made  of  a 
single  article ;  although  a  single  indigestible  article  may  inter- 
fere with  the  reduction  of  articles  that  are  easily  digested. 
(Bead  Note  10.) 

stomachs  examined.  It  was  found  that  the  hound  that  hunted  still  had 
the  stomach  full  of  food,  while  that  of  the  stay-at-home  was  empty. 
When  you  have  a  hard  piece  of  work  on  hand  do  not  eat  much ;  the 
more  you  eat  the  weaker  you  are  for  the  purpose." — Buckland  (in  part). 
10.  Digestibility  of  Warm  Food.  —  "It  is  very  desirable  that  all 
cooked  food  should  be  taken  hot.  When  it  is  eaten  cold  it  reduces  the 
temperature  of  the  stomach,  and  both  the  nerves  and  vessels  of  the 
stomach  are  taxed  in  order  to  bring  the  temperature  of  the  food  thus 
taken  up  to  that  of  the  human  body.  Mankind  in  all  ages  seems  to 
have  discovered  that  it  is  desirable  to  prevent  this  tax  upon  the  internal 
organs,  and  have  taken  their  food  hot  in  order  to  prevent  it.  It  was 
death  to  the  Roman  slave  to  bring  in  his.  master's  water  tepid  or  cold  — 
so  much  importance  did  they  attach  to  hot  water  as  drink.  Many  of 
our  own  beverages  are  taken  hot  even  in  summer  weather ;  and  't  is  an 


48.  Circumstances  affecting  duration  of  digestion  ?    Fresh  food  ? 

49.  Food  in  concentrated  form  ?    A  large  quantity  of  food  ?    Experiment  on  the  dog? 
Ice-water  ?    Variety  of  articles  ? 


DIGESTION  143 

50.  Strong  emotion,  whether  of  excitement  or  depression, 
checks  digestion,  as  do  also  a  bad  temper,  anxiety,  business 
cares,  and  bodily  fatigue.     The  majority  of  these  conditions 
make  the  mouth  dry  —  that  is,  they  restrain  the  flow  of  the 
saliva;  and  without  doubt  they  render  the  stomach  dry  also, 
by  preventing  the  flow  of  the  gastric  juice.     And,  as  a  general 
rule,  we  may  decide,  from  a  parched  and  coated  tongue,  that 
the  condition  of  the  stomach  is  not  very  dissimilar,  and  that  it 
is  unfit  for  the  performance  of  digestive  labor.     This  is  one  of 
the  points  which  the  physician  bears  in  mind  when  he  examines 
the  tongue  of  his  patient.     (Head  Note  11.) 

51.  The  practice  of  eating  at  short  intervals,  or  "between 
meals,"  as  it  is  called,  has  its  disadvantage,  as  well  as  rapid 
eating  and  overeating,  since  it  robs  the  stomach  of  its  needed 
period  of  entire  rest,  and  thus  overtasks  its  power.     With  the 
exception  of  infants  and  the  sick,  no  persons  require  food  more 
frequently   than  once   in  six  hours.     Severe  exercise,  either 
directly  before  or  directly  after  eating,  retards  digestion;   a 
period  of  repose  is  most  favorable  to  the  proper  action  of  the 
stomach.     The  natural  inclination  to  rest  after  a  hearty  meal 
may  be  indulged,  but  it  should  not  be  carried  to  the  extent  of 


economy  of  the  vital  powers  to  take  hot  meals  rather  than  cold  ones.  As 
a  rule,  hot  food  is  better  than  cold,  in  our  climate,  except  in  very  hot 
weather ;  in  tropical  climates  only  can  food  be  taken  with  advantage 
when  cold,  or  ice  and  iced  drinks  be  used  with  impunity."  —  Lankester's 
Manual  of  Health. 

11.  On  the  Demands  of  Digestion.  —  "The  system  never  does  two 
things  well  at  the  same  time.  No  one  can  meditate  a  poem  and  drive  a 
saw  simultaneously  without  dividing  his  force ;  he  may  poetize  fairly 
and  saw  poorly ;  or  he  may  saw  fairly  and  poetize  poorly  ;  or  he  may 
both  saw  and  poetize  indifferently.  Brain-work  and  stomach-work  inter- 
fere with  each  other  if  attempted  together.  The  digestion  of  a  dinner 
calls  force  to  the  stomach,  and  temporarily  slows  the  brain  :  the  experi- 
ment of  trying  to  digest  a  hearty  supper,  and  to  sleep  during  the  process, 
has  sometimes  cost  the  careless  experimenter  his  life.  The  physiological 
principle  is  to  do  only  one  thing  at  a  time,  if  you  would  do  it  welL"  — 
Dr.  E.  H.  Clarke :  Sex  in  Education. 


50.  Strong  emotion  ?   The  tongue  of  the  patient  ? 

51.  Eating  between  meals  ?    Severe  exercise  ?    Sleep  after  meals  ? 


144 


DIGESTION 


sleeping ;  since  in  that  state  the  stomach,  as  well  as  the  brain 
and  the  muscles,  seeks  release  from  labor.  (Read  Notes  12  and  13.) 
52.  The  Kidneys.  —  Besides  those  already  described, -the 
abdominal  cavity  contains  other  important  organs,  viz.,  the 
kidneys  and  spleen.  The  kidneys  are  two  in  number,  located  in 

the  loins  behind  the  intestines,  one 
on  each  side  of  the  spinal  column. 
They  are  shaped  like  a  bean,  being 
about  four  inches  long,  two  inches 
wide,  and  one  inch  thick.  The  func- 
tion of  the  kidneys  is  to  purify  the 
blood  by  removing  from  it  a  poison- 
ous substance  called  urea  and  cer- 
tain waste  products.  If  their  action 
is  in  any  way  interfered  with,  blood- 
poisoning  takes  place,  on  account 
of  the  accumulation  of  urea,  and 
effete  materials  in  the  system,  pro- 
ducing coma,  which  rapidly  proves 
fatal  unless  it  is  relieved.  The 
watery  fluid  secreted  by  ths  kid- 
neys is  carried  by  two  tubes,  called 
ureters,  to  the  bladder. 


FIG.  32.  — THE  KIDNEYS  AND 
BLADDER 


12.  Work  of  Exertion. —  "The  best  time  to  make  great  exertion  is 
about  two  hours  after  a  meal.    It  is  not  a  good  time  before  breakfast, 
although  moderate  work  may  be  then  performed ;  and  those  who  go  to 
work  before  breakfast  should  first  take  a  cup  of  hot  milk,  tea,  or  coffee, 
or  other  simple  food.    The  body  is  weakest  before  breakfast. 

u  Violent  or  rapid  exertion  made  by  children,  and  also  by  stout  and 
aged  people,  often  injures,  and  sometimes  causes  disease  of  the  heart, 
when  the  same  taken  in  the  ordinary  way  would  do  no  harm.  Rapidly 
running  upstairs,  or  to  meet  a  train,  sometimes  causes  death.  Hence, 
while  exercise  is  of  the  utmost  importance  to  health,  it  should  be  taken 
in  a  regulated  and  rational  manner,  and  particularly  by  those  who  have 
passed  the  period  of  youth.  But  disease  of  the  heart,  even  in  youth,  may 
often  be  traced  to  indiscretion  in  this  particular,  whether  in  rowing,  run- 
ning, or  jumping."  —  Edward  Smith  on  Health. 

13.  Tight  Clothing  interferes  with  Digestion.  —  "  On  one  wet  winter's 
day  at  Florence,  some  years  ago,  I  had  been  spending  the  morning  in  the 


52.  What  are  the  kidneys  and  their  functions  ? 


DIGESTION  145 

53.  The  Spleen. — The  spleen  is  situated  on  the  left  side  of 
the  abdomen  behind  the  stomach.     It  is  called  the  "milt"  by 
the  butcher.     It  has  no  duct,  and  its  uses  are  not  positively 
known.     In  malarial  fevers,  it  is  sometimes  much  enlarged, 
and  the  individual  is  said  to  have  an  "  ague  cake." 

54.  Effect  of  Alcohol  upo'n  Digestion.  —  The  irritating  effects 
of  alcohol  upon  the  lining  of  the  stomach*  are  first  seen  in 
deranged  digestive  action,  in  loss  of  appetite,  and  at  a  later 
stage,  in  changes  in  the  stomach's  structure,  principally  by  a 
thickening  of  the  walls  of  that  organ.     (Head  Note  14.) 

studio  of  a  sculptor  of  world-wide  reputation.  We  had  discussed  the 
perfections  of  female  beauty,  and  I  felt  that  I  was  sitting  at  the  feet  of  a 
thinker,  as  well  as  an  '  elegans  formarum  spectator.1  In  the  evening  we 
met  again  at  a  hospitable  palazzo,  and,  under  cover  of  the  waltz,  from  a 
quiet  corner  of  observation,  we  saw  hurling  by  in  the  flesh,  much  that  we 
had  been  thinking  of  in  the  marble  and  the  clay,  and  our  eyes  could  not 
but  follow  one  particular  face,  famous  for  the  assistance  its  great  natural 
beauty  received  from  art.  4  Face,'  I  said,  but  the  mind  of  Hiram  Powers 
was  penetrating  deeper,  for  he  exclaimed,  after  a  short  silence  :  '  That 

is  all  very  well,  but  I  want  to  know  where  Lady puts  her  liver  I* 

Where,  indeed !  for,  calculating  the  circumference  of  the  waist  by  the 
eye,  allowing  a  minimum  thickness  for  the  walls  of  the  chest,  an  area  for 
the  spine,  oesophagus,  and  great  blood-vessels,  the  section  of  the  waist 
seemed  to  admit  of  no  room  for  anything  else.  In  such  a  body  the  liver 
must  be  squeezed  down  into  the  abdomen,  stick  into  its  hollow  neighbors, 
and  infringe  upon  all  the  organs.  The  organ  which  suffers  most  is  the 
unresisting  stomach,  which  is  dragged  and  pushed  out  qf  all  form  during 
the  continuance  of  this  packing  process."  — Dr.  T.  K.  Chambers  on  the 
Indigestions. 

*  Dyspepsia  due  to  Alcohol. —  "Many  cases  of  dyspepsia  are  due  to 
alcohol  solely  and  wholly,  and  no  reliance  whatever  can  be  placed  upon 
the  word,  statement,  or  assertion  under  oath  of  a  drunkard;  for  'a 
drunkard  is  a  liar.'  And  this  holds  good  of  both  sexes,  all  ages,  every- 
where and  ever."  —  Dr.  J.  M.  Pother  gill. 

14.  Cordials,  Bitters,  etc.  —  "In  health,  alcohol  no  wise  plays  a 
friendly  part  in  regard  to  digestion.  And  it  is  just  here  that  a  mistake 
is  made  by  many  persons  who  have  been  deluded  into  the  use  of  what 
are  termed  '  cordials ' ;  these  are  very  strong  alcoholic  liquors,  and  they 
are  supposed  by  those  who  use  them  to  be  especially  appropriate  at  the 
end  of  a  hearty  meal.  Absinthe,  the  pet  poison  of  the  Parisian,  is  one  of 
these  falsely-named  '  cordial  'substances.  These  cordials  are  never  less 


53.  What  is  the  location  of  the  spleen  ? 

54.  How  ia  the  digestion  affected  by  alcohol  f 


146  DIGESTION 

Dr.  Beaumont  was  able  to  observe  the  condition  of  the 
stomach  of  Alexis  St.  Martin  (see  paragraph  28,  page  128)  after 
alcoholic  excesses.  He  states  that  the  surface  of  the  organ  was 
overcharged  with  blood,  at  times  drops  of  blood  exuding  from 
it ;  and  that  its  secretions  became  thick,  unnatural,  and  slightly 
tinged  with  blood.*  It  is  a  fact  beyond  dispute  that  other 
organs  concerned  in  the  act  of  digestion,  particularly  the  liver, 
become  diseased  by  the  habitual  use  of  spirituous  liquors. 
(Head  Note  15.) 

55.  Effects  of  Alcohol  on  the  Liver. —  When  alcohol  is  taken 
into  the  stomach  it  is  absorbed,  and  is  carried  by  the  portal 
vein  directly  into  the  liver.  The  blood  in  the  liver  is  thus 
made  more  stimulating,  and  repeated  stimulation  produces 
over-action,  which  results  in  impairment  or  loss  of  power  to 
secrete  healthy  bile.  For  the  same  reason,  organic  changes 
take  place  more  frequently  in  the  liver,  from  the  use  of  alcohol, 

welcome  than  after  a  substantial  meal.  So  many  misleading  names  have 
been  given  to  beverages  (Cordials,  Bitters,  etc.),  that  many  persons  have 
used  them  without  knowing  the  evil  consequences  which  follow.  It  is 
made  clear  by  recent  proofs  that  the  so-called  cordials  are  the  most  rapidly 
poisonous  of  all  the  spirituous  beverages." 

*  Alcohol  and  Digestion.  —  "The  effects  of  alcohol  upon  digestion  vary 
greatly  according  to  the  quantity  imbibed  ;  it  may  act  as  a  temporary 
check,  or  in  large  doses  it  may  completely  arrest  the  digestive  act :  vomit- 
ing is  frequently  induced  —  the  stomach  thus  freeing  itself  from  the  hurt- 
ful intruder.  The  habitual  use  of  spirits  often  gives  rise  to  a  most  dis- 
tressing form  of  dyspepsia." 

15.  Effect  upon  the  Appetite.—  "  At  a  Peace  Congress  held  at  Frank- 
fort, Germany,  the  inn-keepers  found  it  necessary  to  increase  the  price 
of  board  of  the  strangers  attending  the  congress,  the  majority  of  whom 
were  teetotalers,  for  the  reason  that  their  appetites  required  an  amount 
of  solid  food  in  excess  of  that  usually  consumed  by  their  own  nationality, 
who  are  habitual  drinkers  of  beer  containing  appreciable  amounts  of 
alcohol. 

"  By  direct  contact,  alcohol  acts  upon  the  stomach  and  leads  to  a 
destruction  of  its  secreting  tubules.  Nothing  with  such  certainty  impairs 
the  appetite  and  the  digestive  power  as  the  continued  use  of  strong  alco- 
holic liquids.  From  the  stomach  it  is  absorbed,  and  with  its  distribution 
through  the  system  it  interferes  with  nutrition  and  leads  to  a  diseased 
state  of  the  liver,  kidneys,  and  other  organs."  —  Pavy. 


66.  What  effect  produced  on  tha  liver  by  alcohol? 


DIGESTION  147 

than  in  any  other  organ.  It  first  becomes  enlarged,  owing  to 
congestion  from  obstruction  of  the  circulation  and  excessive 
growth  of  the  connective  tissue.  One  result  of  this  overgrowth 
is  compression  and  diminution  in  size  of  the  cells  which  secrete 
the  bile.  Another  result  is  a  hindrance  to  the  flow  of  blood 
through  the  liver.  The  organ  is  not  only  diminished  in  size, 
but  it  becomes  hardened  and  roughened  —  an  appearance  which 
has  given  it  the  name  of  hob-nailed  liver  or  drunkard's  liver. 
This  condition  not  only  interferes  with  the  proper  formation 
of  bile,  but  it  obstructs  the  return  of  blood  from  the  organs  in 
the  abdomen,  and  we  have  dropsy  as  a  consequence. 

56.  The  Effects  of  Alcohol  on  the  Kidneys.  —  The  action  of 
alcohol  on  the  kidneys  is  similar  to  that  which  takes  place  in 
the  liver.     The  first  effect  of  repeated  stimulation  by  alcohol 
is  an  increase  of  the  natural  secretions  of  the  organs,  but  this,, 
continued'  over-action,  in  obedience  to  a  universal  law,  after- 
ward results  in  a  diminished  secretion  and  in  injury  to  the 
substance  of  the  kidney.     "  Granular  degeneration,"  one  of 
the  forms  of  Bright's  disease,  takes  place.     The  kidneys  are 
unable  to  perform  efficiently  the  duty  of  removing  impurities 
from  the  blood ;  urea,  and  other  noxious  materials  accumulate, 
and  the  whole  system  is  poisoned. 

57.  The  Effect  of  Tobacco  on  Digestion. — Very  few  persons 
are  able  to  take  up  the  habit  of  smoking  without  first  experi- 
encing the  sickening  effect  of  tobacco  upon  the  stomach.     The 
use  of  tobacco  has  a  perverting  influence  over  the  salivary 
glands,  causing  the  secreted  fluid  to  become  so  watery  as  to 
deprive  it  of  its  property  of  converting  starch  into  cugar.     In 
the  case  of  some  persons  this  amounts  to  a  serious  impairment 
of  digestion,  and  can  be  relieved  only  by  the  abandonment  of 
the  offending  substance. 

The  habitual  use  of  tobacco  has  a  tendency  to  leave  the 
mouth  and  throat  in  a  condition  of  unnatural  dryness,  and  this 
has  the  effect  of  an  artificially  produced  thirst  which  has,  in 


56.  How  are  the  kidneys  affected  by  alcohol  ? 

57.  What  effect  of  tobacco  on  digestion  ?    Upon  the  mouth  ?    What  are  the  "  twin 
vice*"? 


148 


DIGESTION 


many  instances,  led  to  the  habit  of  taking  alcoholic  liquors. 
These  two  habits  do  not  always  co-exist  in  the  same  persons, 
but  the  danger  that  the  one  will  lead  up  to  the  other  is  so 
great  that  they  are  frequently  spoken  of  as  the  "  twin  vices." 

The  young  should  appreciate  this  danger,  and  should  also 
remember  that  the  habit  of  using  tobacco  is  most  commonly 
established  early  in  life,  if  at  all ;  very  few  persons,  compara- 
tively, who  have  passed  twenty  years  of  age  without^  forming 
the  habit,  adopt  it  in  their  later  years. 


TOPICAL    OUTLINE 


THE 

CAVITIES  OP    -I 
THE  TRUNK 


Thorax  or 
Chest 


Diaphragm 


Abdomen  . 


\  Shape 


Walls 


f  Conical,  with  the  diaphragm 
1     as  its  base. 
Back  —  Vertebral  column. 
(  Ribs. 


Sides  — 


Front  — 


/  Intercostal  muscles, 
f  Sternum. 


I  Costal  cartilages. 
Floor  —  Diaphragm. 

(A muscular  partition,  dividing  the  thorax 
from  the  abdomen.  Convex  above  and 
concave  below. 

f  Roof  —  Diaphragm. 
I  Back  —  Vertebral  column. 
1  Sides  arid  Front  —  Abdomi- 
L     nal  muscles. 


Walls 


Absorption  by 
Blood-vessels 


f  Solution  commenced    in  the  mouth  by  the 

Starchy  foods  \     saliva. 

1  Completed  in  the  intestines  by  the  intestinal 
I    juices. 
Solution  commenced  in  the  stomach  by  the 

gastric  fluid.  , 

Continued  in  the  intestines  by  the  pancreatic 
fluid,  and  also  (probably)  by  the  intestinal 
secretions. 

f  Fat  globules  loosened  from  their  nitrogenous 
cell-walls  and  membranes  by  the  gastric 
fluid. 

|  Digested  in  the  intestines  by  the  bile  and  the 
I     pancreatic  fluid. 
Mineral  salts     Dissolved  by  the  various  digestive  fluids. 

From  the  mucous  membrane  in  all  parts  of  the  alimentary 
canal. 

No  power  of  selection  — 

Every  kind  of  food  absorbed  if  dissolved,  or  if  so  finely 
divided  that  it  can  permeate  the  walls  of  the  blood  capil- 
laries. 


p 

Nitrogenous 

PROCESS 

foods 

OF 

DIGESTION 

| 

Fats    .          .  \ 

DIGESTION 


149 


LYMPHATIC 
SYSTEM 


Lacteals 


Other 
Lymphatics 

Glands  . 


>  Thoracic  duct 


Tht  lymphatics  of  the  intestines. 
M*ny  originate  in  the  villi  of   the  small 
intestine. 

f  During  digestion — a  milky  flnid 
Contain  \     (chyle). 

[  During  fasting— a.  watery  fluid. 
Absorb  fatty  substances. 
f  Absorb  the  fluid  portion  of  blood  (lymph) 
which    has   exuded   through   the   blood- 
j      vessels. 

[  Also  other  substances  for  reorganization. 
1  Engaged   in   elaborating   blood    from   the 
1  --  lymph  and  chyle. 
In  front  of  backbone,  chiefly  in  thorax. 
Receptaculum  chyli  —  lower  portion  —  situ- 
ated in  the  abdomen. 

Receives  lymph  and  chyle,  and  pours  them 
into  the  blood  system. 


QUESTIONS    FOR    TOPICAL    REVIEW 

MOB 

1.  What  do  you  understand  by  nutrition  ?. ' 117 

2.  How  is  the  process  of  nutrition  carried  on  ? 117 

3.  What  further  can  you  state  on  the  subject  ? 118 

4.  Describe  the  general  plan  of  digestion ». 119 

5.  How  is  the  process  of  mastication  carried  on  ? 119 

6.  State  what  you  can  in  relation  to  the  formation  of  the  teeth 120,  121 

7.  What,  in  relation  to  their  arrangement  ? 120,  121 

8.  What,  in  relation  to  the  process  of  "  shedding  "  ? 120 

9.  In  relation  to  the  different  forms  of  teeth  in  different  animals  ?  . .  122,  123 

10.  What  causes  operate  to  injure  or  destroy  the  teeth  ? 123 

11.  What  suggestions  and  directions  are  given  for  the  preservation  of 

the  teeth? 123,124 

12.  What  do  you  understand  by  insalivation  ? 124 

13.  How  is  the  process  of  insalivation  carried  on  ? 124,  125 

14.  Of  what  importance  is  the  saliva  to  the  process  ? 125,  126 

15.  Of  what  importance  are  mastication  and  insalivation  ? .   127 

16.  Describe  the  consequences  of  rapid  eating 127,  128 

17.  What  becomes  of  the  food  directly  after  it  has  undergone  mastica- 

_  tion  and  insalivation  ? 128 

18.  Describe  the  location  and  formation  of  the  stomach 128,  129 

19.  Describe  the  process  by  which  the  gastric  juice  is  formed 129,  130 

20.  What  are  the  properties  and  uses  of  the  gastric  juice  ? 130 

21.  What  are  the  movements  of  the  stomach,  and  what  their  uses? 131 

22.  What  further  can  you  state  on  the  subject? 131 

23.  What  portions  of  the  food  are  digested  in  the  stomach  ? 132,  133 

24.  What  are  the  first  changes  of  digestio'n  ? 132 

25.  What  further  can  you  state  in  relation  to  the  stomach  ? 132,  133 

26.  Describe  the  intestines 134 

27.  Describe  the  process  of  intestinal  digestion 134,  135 

28.  What  do  you  understand  by  a-bsorption  ? 136 


150  DIGESTION 


29.  How  is  the  process  of  absorption  effected  ? 137 

30.  What  are  the  lacteals,  and  of  what  use  are  they  ? 138 

31.  What  length  of  time  is  required  for  the  digestion  of  food  ? 141 

32.  What  circumstances,  of  food,  affect  digestion  ? : 142 

33.  What  circumstances,  of  emotion,  affect  digestion  ? 143 

34.  What  suggestions  and  directions  are  given  upon  the  subject  of  eat- 

ing and  drinking  ? 142,  143 

35.  Describe  the  kidneys  and  their  office 144 

36.  What  happens  when  their  action  ceases  ? 144 

37.  Give  the  location  of  the  spleen.    Has  it  a  duct  ? 145 

38.  How  does  alcohol  affect  digestion  ? 145,  146 

39.  Give  the  experiment  on  St.  Martin 146 

40.  State  the  effects  of  alcohol  upon  the  liver 146, 147 

41.  State  the  effects  upon  the  kidneys 147 


CHAPTER  VII 

THE  CIRCULATION 

The  Blood — Its  Plasma  and  Corpuscles — Coagulation  of  the  Blood  — 
The  Uses  of  the  Blood  — Transfusion— Change  of  Color— The  Organs 
of  the  Circulation  —  The  Heart,  Arteries,  and  Veins— The  Cavities 
and  Valves  of  the  Heart  — Its  Vital  Energy  —  Passage  of  the,  Blood 
through  the  Heart—  The  frequency  and  Activity  of  its  Movements  — 
The  Pulse— The  Spygmograph—The  Capillary  Blood-vessels  —  The 
Bate  of  the  Circulation  —  Assimilation  —  Injuries  to  the  L'^od-vessels 
—  E/ects  of  Alcohol  on  Heart 

1.  The  Blood. — Every  living  organism  of  the  higher  sort, 
whether  animal  or  vegetable,  requires  for  the  maintenance  of 
life  and  activity,  a  circulatory  fluid,  by  which  nutriment  is  dis- 
tributed to  all  its  parts.     In  plants,  this  fluid  is  the  sap ;  in 
insects,  it  is  a  watery  and  colorless  blood;   in  reptiles  and 
fishes,  it  is  red  but  cold  blood;  while  in  the  nobler  animals 
and  man,  it  is  red  and  warm  blood. 

2.  The  blood  is  the  most  important,  as  it  is  the  most  abun- 
dant, fluid  of  the  body ;  and  upon  its  presence,  under  certain 
definite  conditions,  life  depends.     On  this  account  it  is  fre- 
quently, and  very  properly,  termed  "the  vital  fluid."     Tne 
importance  of  the  blood,  as  essential  to  life,  was  recognized  in 
the  earliest  writings.     In  the  narration  of  the  death  of  the 
murdered  Abel,  it  is  written,  "the  voice  of  his  blood  crieth 
from  the  ground."     In  the  Mosaic  law,  proclaimed  over  thirty 
centuries  ago,  the  Israelites  were  forbidden  to  eat  food  that 
contained  blood,  for  the  reason  that  "  the  life  of  the  flesh  is  in 
the  blood."    With  the  exception  of  a  few  tissues,  such  as  the 
hair,  the  nails,  and  the  cornea  of  the  eye,  blood  everywhere 
pervades  the  body,  as  may  be  proved  by  puncturing  any  pan 

1 .  What  is  required  by  every  living  organism  ?    In  plants  ?    Insects  ?    Keptiles  ?    Man  ? 

2.  Importance  and  abundance  of  blood  ?     Dependence  of  life  ?    Abel  ?    Mosaic  law  ? 
In  what  part  of  the  body  is  blood  not  found  ?    Quantity  of  blood  in  the  body  f 


152 


THE  CIRCULATION 


with  a  needle.  The  total  quantity  of  blood  in  the  body  is 
estimated  at  about  one-eighth  of  its  weight,  or  eighteen  pounds. 

3.  The  color  of  the  blood,  in  man  and  the  higher  animals, 
as  is  well  known,  is  red;  but  it  varies  from  a  bright  scarlet 
to  a  dark  purple,  according  to  the  part  whence  it  is  taken. 
"Blood  is  thicker  than  water,"  as  the  adage  truly  states,  and 
has  a  glutinous  quality.     It  has  a  faint  odor,  resembling  that 
peculiar  to  the  animal  from  which  it  is  taken. 

4.  When  examined  under   the  microscope,   the  blood  no 
longer  appears  a  simple  fluid,  and  its  color  is  no  longer  red. 
It  is  then  seen  to  be  made  up  of  two  distinct  parts :  first,  a 
clear,  colorless  fluid,  called  the  plasma;  and,  secondly,  of  a  mul- 
titude of  minute  solid  bodies,  or  corpuscles,  that  float  in  the 
watery  plasma.     The  plasma,  or  nutritive  liquid,  is  composed 
of  water  richly  charged  with  materials  derived  from  the  food, 
viz.,  albumen,  which  gives  it  smoothness;  fibrin;  certain  fats; 
traces  of  sugar ;  and  various  salts. 

5.  The  Blood  Corpuscles.  —  In  man,  these  remarkable  "  little 
bodies,"  as  the  meaning  of  the  word  corpuscles  signifies,  are  of 

a  yellow  color,  but  by  their  vast 
numbers  impart  a  red  hue  to  the 
blood.  They  are  very  small,  hav- 
ing a  diameter  of  about  -^^  of  an 
inch,  and  being  one-fourth  of  that 
fraction  in  thickness;  so  that  if 
3500  of  them  were  placed  in  line, 
side  by  side,  they  would  only  ex- 
tend one  inch;  or,  if  piled  one 
above  another,  it  would  take  at 

FIG.  33.— THE  BLOOD  CORPUSCLES,    least  14,000  of  them  to  stand  an 
HIGHLY  *AGNIFIBI>  iu(fo  ^^     Although   so  small  in 

size  they  are  very  regular  in  form.  As  seen  under  the  micro- 
scope, they  are  not  globular  or  spherical,  but  flat,  circular,  and 
disc-like,  with  central  depressions  on  each  side,  somewhat  like 


8.  Color  of  blood  ?    Its  consistence  ?    Odor  ? 

4.  What  is  stated  of  the  blood  as  viewed  under  the  microscope  ? 

6.  State  what  you  can  of  the  little  bodies  called  corpuscles. 


THE  CIRCULATION 


153 


a  pearl  button  that  has  not  been  perforated.  In  freshly-drawn 
blood  they  show  a  disposition  to  arrange  themselves  in  little 
rolls  like  coins  (Fig.  33). 

6.  The  size  and  shape  of  blood  (red)  corpuscles,  vary  in  dif- 
ferent animals.    In  man  they  are  circular  and  flat,  with  a  central 
depression  on  both  sides,  also  in  all  warm-blooded  quadrupeds, 
except  the  camel  and  lama,  where  they  are  oval.     In  birds, 
reptiles,  and  fish,   they  are  oval,  but   with 

raised  centre  or  nucleus.    .This  variation  is  (§&   *" 

often  of  vital  importance  in  murder  trials,  ®  ^ 

where  blood-stained  weapons  or  clothing  are 
used  as  evidence.  A  microscopical  examina- 
tion shows  us  the  corpuscles,  and  we  deter- 
mine from  their  shape,  whether  it  was  caused 
by  blood  from  a  warm-blooded  quadruped, 
from  a  camel,  or  from  a  fowl  or  fish.  But 
we  cannot  affirm  that  the  stain  was  made  by 
human  blood,  and  not  by  that  of  the  dog,  ox, 
or  sheep,  because  in  all  of  these  the  corpuscles 
are  shaped  alike,  and  the  size  varies  but  little. 

7.  The  character  of  the  blood  of  dead,  ex- 
tinct, and  even  fossil  animals,  such  as  the  corpuscles  o'f  a  'frog,  c', 
mastodon,  has  been  ascertained  by  obtaining  T^e  file  sm^n  ones  at 
and  examining  traces  of  it  which  had  been  the  upper  part  of  the 
shut  up,  perhaps  for  ages,  in  the  circulatory  ^7^^"!  m^n"- 
canals  of  bone.     A  means  of  detecting  blood  fled  four  hundred  times. 
in  minute  quantities  is  found  in  the  spectroscope,  the  same 
instrument  by  which  the  constitution  of  the  heavenly  bodies 
has  been  studied.     If  a  solution  containing  not  more  than  one 
one-thousandth  part  of  a  grain  of  the  coloring  matter  of  the 
corpuscle  be  examined,  this  instrument  will  detect  it. 

8.  The  red  corpuscles  are  of  a  soft  and  jelly-like  consistency, 
without  any  distinctive  cell  membrane  enclosing  them.     Some 
observers  have  claimed  that  this  latter  does  exist,  but  it  can- 
not be  demonstrated.     They  are  composed  of  an  albuminous 
substance  and  a  coloring  matter,  called  haemoglobin,  together 


Fie.     84.  —  a,    Oval 
Corpuscles  of  a  fowl.  6, 


6.  Size  and  shape  of  the  red  corpuscles  ?    7.   How  may  blood  in  minute  quantities  be 
ietect«d  1    8.  Describe  the  structure  and  constitution  of  the  red  corpuscles. 


154  THE  CIRCULATION 

with  mineral  salts  and  water,  the  latter  constituting  more  than 
half  the  bulk.  The  coloring  matter,  haemoglobin,  has  the 
power  of  readily  absorbing  oxygen,  wherever  that  gas  is  found, 
and  with  equal  facility  parting  with  it  wherever  it  is  needed. 
Thus  it  is  that  the  blood  in  its  passage  through  the  lungs 
absorbs  the  oxygen  from  the  air,  or  as  much  of  it  as  is  needed. 
As  the  blood  circulates  throughout  the  tissues  of  the  body,  it 
supplies  them  with  their  needed  oxygen. 

9.  Besides  these  corpuscles,  and  floating  along  in  the  same 
plasma,  are  the  white  corpuscles.     These  are  fewer  in  number, 
but  larger,  and  globular  in  form.     They  are  colorless,  and  their 
motion  is  less  rapid  than  that  of  the  other  variety.     The  total 
number  of  both  varieties  of  these  little  bodies  in  the  blood  is 
enormous.     It  is  calculated  that  in  a  cubic  inch  of  that  fluid 
there  are  eighty-three  millions,  and  at  least  five  hundred  times 
that  number  in  the  whole  body. 

10.  The  white  blood  corpuscles  exist  in  the  blood,  in  the 
proportion  of  about  one  to  three  hundred  of  the  red.     They 
are  nearly  spherical  in  form,  and  are  about  one-half  as  large 
again  in  diameter  as  the  red  ones.     They  consist  of  a  soft, 
somewhat  viscid,  finely  granular  substance,  containing  one  or 
more  ovoid  nuclei.     They  are  less  yielding  and  slippery  than 
the  red,  and  adhere  more  readily  to  any  surface  with  which 
they  come  in  contact.     If  the  blood  in  circulation  in  the  web 
of  the  frog's  foot  be  examined,  it  will  be  seen  that  the  red 
globules  form  the  centre  of  the  current,  whilst' the  white  are 
often  seen  along  the  walls  of  the  blood-vessel.     They  are  capa- 
ble of  independent  movement,  resembling  in  this  the  amoeba, 
already  spoken  of  in  the  first  chapter ;  by  means  of  this  inde- 
pendent motion  they  are  enabled  to  move  from  place  to  place, 
and  even  pass  through  the  walls  of  the  capillaries  into  the  sur- 
rounding tissue.     Nothing  definite  is  known  about  their  physi- 
ological functions.     That  they  play  an  important'part  in  the 
economy  of  the  body  cannot  be  doubted  as  judged  from  the 
fact  that    they  are   present    in   such    considerable    numbers. 
Some  observers  claim  that  they  have  an  important  part  in  the 

9,  Si?e,  shape,  and  color  of  wUite  corpuscles  ?    10.  Proportion  of  whjte  to  red  corpuscles  ? 


THE  CIRCULATION  155 

function  of  nutrition,  being  carriers  of  peptone  and  fat. 
Others  claim  that  they  act  as  destroyers  of  bacteria,  acting 
in  this  way  as  general  scavengers  of  the  body.  But  neither 
these  nor  any  other  of  the  many  theories  advanced  as  to  the 
functions  of  the  white  corpuscles  is  capable  of  positive  demon- 
stration. (Read  Note  1.) 

11.  Coagulation.  —  The  blood,  in  its  natural  condition  in  the 
body,  remains  perfectly  fluid ;  but  within  a  few  minutes  after 
its  removal  from  its  proper  vessels,  a  change  takes  place.     It 
begins  to  coagulate,  or  assume  a  semi-solid  consistence.     If 
allowed  to  stand,  after  several  hours  it  separates  into  two 
distinct  parts,  one  of   them  being  a  dark  red  jelly,  called 
the  coagulum,  or  clot,  which  is   heavy  and  sinks ;   and  the 
other,  a  clear,  straw-colored  liquid,  called  serum,  which  covers 
the  clot.     This  change  is  dependent  upon  the  presence  in  the 
blood  of   fibrin,  which  possesses  the  property  of  solidifying 
under  certain  circumstances,  one  of  them  being  the  separation 
of  the  blood  from  living  tissues.    The  color  of  the  clot  is  due  to 
the  entanglement  of  the  corpuscles  with  the  fibrin. 

12.  In  this  law  of  the  coagulation  of  the  blood  is  our  safe- 
guard against  death  by  hemorrhage,  or  undue  loss  of  blood.    If 

I.  The  Blood.  —  "  You  feel  quite  sure  that  blood  is  red,  do  you  not  ? 
Well,  it  is  no  more  red  than  the  water  of  a  stream  would  be  if  you  were 
to  fill  it  with  little  red  fishes.    Suppose  the  fishes  to  be  very,  very  small  — 
as  small  as  a  grain  of  sand  —  and  closely  crowded  together  through  the 
whole  depth,  of  the  stream,  the  water  would  look  red,  would  it  not? 
And  this  is  the  way  in  which  the  blood  looks  red  :  only  observe  one 
thing  —  a  grain  of  sand  is  a  mountain  in  comparison  with  the  little  red 
bodies  that  float  in  the  blood,  which  we  have  likened  to  little  fishes.     If 
I  were  to  tell  you  they  measured  about  the  3200th  part  of  an  inch  in 
diameter,  you  would  not  be  much  the  wiser ;  but  if  I  tell  you  that  in  a 
single  drop  of  blood,  such  as  might  hang  on  the  point  of  a  needle,  there 
are  a  million  of  these  bodies,  you  will  perceive  that  they  are  both  very 
minute  and  very  numerous.     Not  that  any  one  has  ever  counted  them, 
as  you  may  suppose,  but  this  is  as  close  an  estimate  as  can  be  made  in 
view  of  what  is  known  of  their  minute  size."  —  Mace's  History  of  a 
Mouthful  of  Bread.        

II.  The  blood  in  its  natural  condition  in  the  body  ?    Describe  the  process  by  which  the 
coagulation  of  blood  takes  place. 

12.   If  coagulation  were  impossible  ?    How  is  it  in  fact  ? 


156  THE  CIRCULATION* 

coagulation  were  impossible,  the  slightest  injury  in  drawing 
blood  would  prove  fatal.  Whereas  now,  in  many  cases,  bleed- 
ing ceases  spontaneously,  because  the  blood,  as  it  coagulates, 
stops  the  mouths  of  the  injured  blood-vessels.  In  another  class 
of  cases,  where  larger  vessels  are  cut  or  torn,  it  is  ordinarily 
sufficient  to  close  them  by  a  temporary  pressure  ;  for  in  a  few 
minutes  the  clot  will  form  and  seal  them  up.  In  still  more 
serious  cases,  where  the  blood-vessel  is  of  large  size,  the  sur- 
geon is  obliged  to  tie  a  ligature  about  it,  thus  preventing  the 
force  of  the  blood-current  from  washing  away  the  clots,  which, 
forming  within  and  around  the  vessel,  close  it  effectually. 

13.  It  is  worthy  of  remark  that  this  peculiarity  is  early 
implanted  in  the  blood,  even  before  birth,  and  in  advance  of 
any  existing  necessity  for  it  —  thus  anticipating  and  guarding 
against  danger.  But  this  is  not  all.  Of  most  of  the  inferior 
animals,  which,  as  compared  with  man,  are  quite  helpless,  the 
blood  coagulates  more  rapidly,  and  in  the  case  of  the  birds, 
almost  instantly.  The  relative  composition  of  fluid  and  coagu- 
lated blood  may  be  thus  represented  : 

Fluid  Blood  Coagulated  Blood 

Plasma;—   -  Serum  —        —  Serum 


Corpuscles  -  Corpuscl 

(Bead  Note  2.) 

14.  The  Uses  of  the  Blood.  —  The  blood  is  the  great  pro- 
rider  and  purifier  of  the  body.  It  both  carries  new  materials 
to  all  the  tissues,  and  removes  the  worn-out  particles  of  matter. 

2.  Experiment.  Coagulation  of  Blood.  —  The  coagulation  of  blood 
can  be  shown  to  a  class  with  but  little  trouble.  Obtain  from  a  butcher  or 
slaughter-house  about  a  pint  of  fresh  blood,  have  it  drawn  into  a  tin  can 
or  pail,  and  put  it  immediately  into  a  freezing  mixture  of  ice  and  salt.  If 
it  be  during  the  winter  and  freezing,  this  is  not  necessary,  as  freezing 
suspends  coagulation. 

18.  What  Is  worthy  of  remark  ?  Coagulation  of  the  blood  of  inferior  animals  ?  Of  the 
blood  of  birds? 

14.  The  blood,  as  a  provider  and  purifier  ?  What  uses  does  the  blood  subserve  ?  Ex- 
periments ?  Transfusion  ? 


THE  CIRCULATION  167 

This  is  effected  by  the  plasma.  It  both  conveys  oxygen  and 
removes  carbonic  acid.  This  is  done  through  the  corpuscles. 
Some  singular  experiments  have  been  tried  to  illustrate  the 
life-giving  power  of  the  blood.  An  animal  that  has  bled  so 
freely  as  to  be  at  the  point  of  death,  is  promptly  brought  back 
to  life  by  an  operation  called  transfusion,  by  which  fresh  blood 
from  a  living  animal  is  injected  into  the  blood-vessels  of  his 
body.  (Read  Note  3.) 

15.  It  is  related  that  a  dog,  deaf  and  feeble  from  age,  had 
hearing  and  activity  restored  to  him  by  the  introduction  into 
his  veins  of  blood  taken  from  a  young  dog;  and,  that  a  horse, 
twenty-six  years  old,  having  received  the  blood  of  four  lambs, 
acquired  new  vigor.     And  further,  that  a  dog,  just  dead  from 
an  acute  disease,  was  so  far  revived  by  transfusion,  as  to  be 
able  to  stand  and  make  a  few  movements. 

16.  Transfusion  has  been  practised  upon  man.     At  one  time, 
shortly  after  Harvey's  discovery  of   the  "Circulation  of  the 
Blood,"  it  became  quite  a  fashionable  remedy,  it  being  thought 

Fill  a  glass  vessel  with  the  blood,  and  observe  the  different  steps  in  its 
coagulation.  In  about  two  to  three  minutes  it  becomes  viscid,  and  after 
about  five  to  ten  minutes  it  has  assumed  a  jelly-like  character,  so  that  the 
vessel  can  be  turned  over  without  spilling  its  contents.  Now  will  be  seen 
on  the  surface  of  the  jelly  a  few  drops  of  fluid,  which  rapidly  multiply, 
so  that  soon  a  layer  of  straw-colored  fluid  is  floating  on  the  surface.  This 
fluid  increases,  and  the  clot  contracts  more  and  more,  until  at  the  end  of 
about  twelve  hours,  the  process  is  complete,  and  we  have  a  firmly  con- 
tracted clot  floating  in  a  clear  straw-colored  fluid.  The  clot  is  composed 
of  the  fibrin  and  corpuscles,  and  the  fluid  is  the  serum,  colored  by  a  few 
red  corpuscles. 

3.  The  Work  of  the  Blood.  — "The  blood,  which  is  our  life,  is  a 
complex  fluid.  It  contains  the  materials  out  of  which  the  tissues  are 
made,  and  also  the  debris  which  results  from  the  destruction  of  the  same 
tissues,  —  the  worn-out  cells  of  brain  and  muscle,  —  the  cast-off  clothes 
of  emotion,  thought,  and  power.  It  is  the  common  carrier,  conveying 
unceasingly  to  every  gland  and  organ,  the  fibrin  and  albumen  which 
repair  their  constant  waste,  thus  supplying  their  daily  bread.  Like  the 
water  flowing  through  the  canals  of  Venice,  that  carries  health  and  wealth 
to  the  portals  of  every  house,  and  filth  and  disease  from  every  doorway, 


16.  The  case  of  the  deaf  and  feeble  dog  ?    Horse?    Dead  dog? 

16.  Transfusion,  as  a  fashionable  remedy  ?    What  further  of  transfusion  * 


158  THE  CIRCULATION 

possible  by  it  to  cure  all  forms  of  disease,"  and  even  to  make 
the  old  young  again.  But  these  claims  were  soon  found  to  be 
extravagant,  and  many  unhappy  accidents  occurred  in  its  prac- 
tice; so  that  being  forbidden  by  government  and  interdicted 
by  the  Pope,  it  rapidly  fell  into  disuse.  At  the  present  time, 
however,  it  is  sometimes  resorted  to  in  extreme  cases,  when 
there  has  been  a  great  and  rapid  loss  of  blood ;  and  there  are 
upon  record  several  instances  where,  other  means  having 
failed,  life  has  been  restored  or  prolonged  by  the  operation  of 
transfusion. 

17.  This  reviving  power  of  the  blood  seems  to  reside  in  the 
corpuscles;  for  transfusion,  when  performed  with  the  serum 
alone,  has,  in  every  case,  proved  fruitless.     Now,  though  so 
much  depends  upon  the  blood  and  its  corpuscles,  it  is  a  mis- 
take to  suppose  that  in  them  alone  is  the  seat  of  life,  or  that 
they  are,  in  an  exclusive  manner,  alive.     All  the  organs  and 
parts  of  the  body  are  mutually  dependent  one  upon  the  other, 
and  the  complete  usefulness  of  any  part  results  from  the  har- 
monious action  of  the  whole. 

18.  Change  of  Color.  —  The   blood  undergoes   a  variety   of 
changes  in  its  journey  through  the  system.     As  it  visits  the 
different  organs  it  both  gives  out  and  takes  up  materials.     In 
one  place  it  is  enriched,  in  another  it  is  impoverished.     By 
reason  of  these  alterations  in  its  composition,  the  blood  alsd 
changes  its  color.     In  one  part  of  the  body  it  is  bright  red,  or 
arterial ;  in  another  it  is  dark  blue,  or  venous.     In  the  former 
case  it  is  pure,  and  fit  for  the  support  of  the  tissues ;  in  the 
latter,  it  is  impure  and  charged  with  effete  materials.     (The 
details  of  the  change  from  dark  to  bright  will  be  given  in  the 
chapter  on  Respiration.)     (Read  Notes  4,  5,  and  6.) 

the  blood  flowing  through  the  canals  of  our  organization  carries  nutriment 
to  all  tissues,  and  refuse  from  them."  —  darkens  Sex  in  Education. 

4.  On  Purifying  the  Blood.  —  "  By  some  the  blood  is  regarded  as  the 
source  of  all  diseases,  and  to  'purify  the  blood'  is  the  object  of  their 
treatment.  Quacks  seize  on  this  notion,  and  in  sublime  ignorance  of  the 


17.  The  seat  of  the  reviving  power  of  the  blood  ?    What  further  is  related  ? 

18.  Changes  in  the  blood  ?    What  further  is  stated  ? 


THE  CIRCULATION  159 

19.  Circulation.  —  The  blood  is  in  constant  motion  during 
life.  From  the  heart,  as  a  centre,  a  current  is  always  setting 
toward  the  different  organs ;  and  from  these  organs  a  current 
is  constantly  returning  to  the  heart.  In  this  way  a  ceaseless 
circular  movement  is  kept  up,  which  is  called  the  Circulation 
of  the  Blood.  This  stream  of  the  vital  fluid  is  confined  to 
,  certain  fixed  channels  —  the  blood-vessels.  Those  branching 
from  the  heart  are  the  arteries ;  those  converging  to  it  are  the 
veins.  The  true  course  of  ~the  blood  was  unknown  before  the 
beginning  of  the  seventeenth  century.  In  1G19  it  was  dis- 
covered by  the  illustrious  William  Harvey.  Like  many  other 
great  discoverers,  he  suffered  persecution  and  loss,  but  unlike 
some  of  them,  he  was  so  fortunate  as  to  conquer  and  survive 
opposition.  He  lived  long  enough  to  see  his  discovery  uni- 
versally accepted,  and  himself  honored  as  a  benefactor  of 
mankind. 

nature  of  the  blood  they  profess  to  purify,  and  of  the  means  by  which 
their  drugs  could  possibly  purify  it,  make  fortunes  out  of  the  credulity  of 
the  public.  I  would  warn  you  against  this  notion  of  'purifying'  the 
blood.  The  blood  is  not  like  a  river  into  which  anything  can  be  intro- 
duced from  without.  It  gets  rid  of,  or  destroys,  all  substances  which 
intrude  —  all  which  do  not  form  part  and  parcel  of  its  own  structure  ;  or, 
failing  in  that,  it  ceases  to  act  as  living  blood."  —  George  Henry  Lewes. 

5.  By  Means  of  the  Blood,  Exercise  Benefits  the  Whole  Body. — 
"The  employment  of  the  muscles  in  exercise  not  only  benefits  their 
especial  structure,  but  it  acts  on  the  whole  system.  When  the  muscles 
are  put  in  action,  the  capillary  blood-vessels  with  which  they  are  supplied 
become  more  rapidly  charged  with  blood,  and  active  changes  take  place, 
not  only  in  the  muscles,  but  in  all  the  surrounding  tissues.  The  heart  is 
thus  required  to  supply  more  blood,  and  accordingly  beats  more  rapidly 
in  order  to  supply  the  demand.  A  large  quantity  of  blood  is  sent  through 
the  lungs,  and  larger  supplies  of  oxygen  are  taken  in  and  carried  to  the 
various  tissues  of  the  body."  The  oxygen  engenders  a  large  amount  of 
heat,  which  produces  an  action  on  the  skin  whereby  the  increase  of  heat 
may  be  got  rid  of.  By  this  means  the  skin  is  exercised,  the  perspiration 
is  poured  forth,  the  surface  is  caused  to  glow  and  is  kept  in  health. 
f  "  Not  only  are  these  organs  benefited  by  the  increased  circulation  of  the 
blood,  produced  by  exercise,  but  wherever  the  blood  is  sent,  changes  of  a 
healthful  character  occur.  The  brain  and  the  rest  of  the  nervous  system 
are  invigorated  ;  the  stomach  has  its  powers  of  digestion  improved  ;  and 


19.   Motion  of  the  blood  ?    What  is  meant  by  the  circulation  of  the  blood  ?    How  con* 
fined  »    Discovery  made  by  Harvey  f 


160  THE  CIRCULATION 

20.  The  Heart.  —  The  heart  is  the  central  engine  of  the  cir- 
culation. In  this  wonderful  little  organ,  hardly  larger  than 
a  man's  fist,  resides  that  sleepless  force  by  which,  during  the 
whole  of  life,  the  current  of  the  blood  is  kept  in  motion.  It 
is  placed  in  the  middle  and  front  part  of  the  chest,  inclining 
to  the  left  side.  The  heart-beat  may  be  felt  and  heard  between 
the  fifth  and  sixth  ribs,  near  the  breast-bone.  The  shape  of 
the  heart  is  conical,  with  the  apex  or  point  downward  and  in 

the  liver,  pancreas,  and  other  organs  perform  their  functions  with  more 
vigor."  — Lankester's  Manual  of  Health. 

6.  Experiment.  The  Heart.  —  To  demonstrate  the  physiological 
anatomy  of  the  heart  will  require  some  dissecting,  and  a  little  more  care 
and  work  than  the  other  experiments,  but  the  teacher  will  be  fully 
rewarded  by  the  close  attention  and  great  interest  shown  by  the  pupils. 

Obtain  from  your  butcher  a  bullock's  heart  inclosed  in  the  pericardium 
or  u  bag."  Instruct  him  to  cut  it  out  carefully  and  as  high  up  as  he  can, 
so  as  not  to  injure  it,  and  so  as  to  leave  of  the  large  blood-vessels  as  much 
attached  as  is  possible. 

Cut  away  all  the  fat  surrounding  the  heart  and  great  blood-vessels ; 
cut  open  the  pericardium  from  apex  to  base,  and  partly  away  from  the 
latter,  so  as  to  give  room  for  exposing  the  cavities  of  the  heart.  The 
latter  should  be  opened  by  two  incisions  along  the  septum  separating  the 
right  from  the  left  heart.  The  incision  should  run  from  apex  to  base, 
laying  open  both  ventricle  and  auricle.  Cut  open  all  the,  large  vessels 
found  at  the  base,  into  the  cavities  to  which  they  lead. 

Going  from  without  inward  observe  and  explain  the  different  parts  as 
follows : 

1.  THE  PERICARDIUM. — Note  its  structure  and  smooth,  shining  inner 
surface.    Show  how  it  surrounds  the  heart,  and  how  it  is  attached  along 
the  base  and  great  blood-vessels. 

2.  GENERAL  STRUCTURE  OF  THE  HEART.  —  Show  the  thin-walled  auri- 
cles ;  the  difference  between  the  thickness  of  the  walls  of  the  ventricles  ; 
the  difference  in  structure  between  the  arteries  and  veins ;  demonstrate 
the  two  coronary  arteries  and  their  accompanying  veins. 

3.  RIGHT  AURICLE  AND  VENTRICLE.  — Demonstrate  the  venae  cavse  and 
their  entrance  into  the  auricle ;  the  auriculb-ventricular  valves  between 
the  two  cavities  ;  the  structure,  attachment,  and  action  of  the  valves ;  the 
pulmonary  artery. 

4.  LEFT  AURICLE  AND  VENTRICLE.  —  Demonstrate  the  pulmonary  veins 
and  their  entrance  into  the  auricle  ;  the  mitral  valve  between  auricle  and 
ventricle ;  the  aortic  valve,  its  structure,  action,  and  attachment ;  the 
structure  and  great  strength  of  the  aorta. 


20.  Office  of  the  heart  ?    Location  of  the  heart  ?    Its  beat  ?    Its  shape  ?    Protection  to 
the  heart  ?    What  else  is  said  in  relation  to  the  heart  ? 


THE  CIRCULATION'  161 

front.  The  base,  which  is  upward,  is  attached  so  as  to  hold  it 
securely  in  its  place,  while  the  apex  is  freely  movable.  In 
order  that  loss  of  power  from  friction  may  be  obviated,  the 
heart  is  enclosed  between  two  layers  of  serous  membrane, 
which  forms  a  kind  of  sac.  This  membrane,  called  the  peri- 
c<ir<Hnm,  is  as  smooth  as  satin,  and  itself  secretes  a  fluid  in 
sufficient  quantities  to  keep  it  at  all  times  well  lubricated. 
The  lining  membrane  of  the  heart,  called  the  endocardium,  is 

extremely  delicate  and  smooth.     (Head  Note  7.) 

% 

21.  The  Cavities  of  the  Heart.  — The  heart  is  hollow,  and  so 
partitioned  as  to  contain  four  chambers  or  cavities ;  two  at  the 
base,  known  as  the  auricles,  from  a  fancied  resemblance  to  the 
ear  of  a  dog,  and  two  at  the  apex  or  point,  called  ventricles. 
An  auricle  and  a  ventricle  on  the  same  side  communicate  with 
each  other,  but  there  is  no  opening  from  side  to  side.     It  is 
customary  to  regard  the  heart  as  a  double'  organ,  and  to  speak 
of  its  division  into  the  right  and  left  heart.     For  while  both 
halves  act  together  in  point  of   time,  each  half  sustains  an 
entirely  distinct  portion  of  the  labor  of  the  circulation.     The 
right  side  always  carries  the  dark  or  venous  blood,  and  the 
left  always  circulates  the  bright  or  arterial  blood. 

22.  If  "we  examine  the  heart,  we  at  once  notice  that,  though 
its 'various  chambers  have  about  the  same  capacity,  the  walls 
of  the  ventricles  are  thicker  and  stronger  than  those  of  the 
auricles.     This  is  a  wise  provision,  for  it  is  by  the  powerful 
action  of  the  ventricles'  that  the  blood  is  forced  to  the  most 
remote  regions  of  the  body.     The  auricles,  on  the  contrary, 
need  much  less  power,  for  they  simply  discharge  their  contents 
into  the  ventricles  below.     (Figs.  35  and  36.)     (See  Note  6.) 

The  two  ventricles,-  moreover,  are  upon  different  levels. 
The  right  ventricle  is  somewhat  in  front  of  and  above  the 
left,  so  that,  in  viewing  the  heart  from  the  front,  we  would 
look  at  the  right  ventricle,  and  in  viewing  the  heart  from  be- 
hind, at  the  left ;  the  left  ventricle,  being  longer  and  narrower 
than  the  right,  and  projecting  below  the  right,  forms  the  apex 

21.   Formation  of  the  heart  ?    Right  and  left  heart  ? 

82.   Capacity  of  the  chambers  of  the  heart  ?    The  auricles  f 


162 


THE  CIRCULATION 


of  the  heart.  The  difference  in  the  thickness  of  the  walls  of 
the  two  ventricles  is  accounted  for  by  the  fact  that  the  right, 
having  thinner  walls  than  the  left,  has  only  to  pump  the  blood 
through  the  lungs,  whereas  the  left  ventricle  has  to  pump  the 
entire  volume  of  blood  through  the  whole  body.  The  valves 
separating  the  different  chambers  of  the  heart  are  named  as  fol- 
lows :  that  between  the  right  auricle  and  right  ventricle  is  called 
the  tricuspid;  that  separating  the  left  auricle  from  the  left 
ventricle,  the  mitral.  There  are  also  two  sets  of  valves  guard- 
ing the  exit  from  the  ventricles,  called  the  semi-lunar  valves. 

23.  Action  of  the  Heart.  —  The  substance  of  the  heart  is  of  a 
deep  red  color,  and  its  fibres  resemble  those  of  the  voluntary 
muscles  by  which  we  move  our  limbs.  But  the  heart's  move- 
ments are  entirely  involuntary.  The  advantage  of  this  is 
evident ;  for  if  it  depended 
upon  us  to  will  each  move- 
ment, our  entire  attention 
would  be  thus  engaged,  c. 
and  we  would  find  no  time 
for  study,  pleasure,  or  even 
sleep.  The  action  of  the 
heart  consists  in  alternate 
contractions  and  expan- 
sions. During  contraction 
the  walls  come  forcibly  to- 
gether, and  thus  drive  out 
the  blood.  They  then  ex- 
pand and  receive  a  renewed 
supply.  These  movements 
are  called  respectively  sys- 
tole and  diastole.  The  latter  FlG.  37>_  SECTION  OF  THE  HEART 

maybe   Called  the    heart's     A,  Right  Ventricle    E,  F,  Inlets  to  the  Ventricles 
n      .       B,  Left  Ventricle       G,  Pulmonary  Artery 

period  of  repose;  and  al-    c,  Right  Auricle      H,  Aorta 

though  it  lasts  only  during    D>  Left  Auricle 

two-fifths  of  a  heart-beat,  or  about  a  third  of  a  second,  yet 

during  the  day  it  amounts  to  more  than  nine  hours  of  total  rest. 


23.  Substance  of  the  heart?     Its  fibres?     Its  movements? 
movements  ?    Action  of  the  heart  ?    Its  period  of  rest  ? 


The  advantage  of  such 


THE  CIRCULATION 


163 


24.  A  remarkable  property  of  the  tissue  of  the  heart  is  its 
intense  vitality.  For  while  it  is  more  constantly  active  than 
any  other  organ  of  the  body,  it  is  the  last  to  part  with  its  vital 
energy.  This  is  especially  interesting  in  view  of  the  fact  that 
after  life  is  apparently  extinguished,  as  from  drowning,  or 
poisoning  by  chloroform,  there  yet  lingers  a  spark,  of  vitality 
in  the  heart,  which,  by  continued  effort,  may  be  fanned  into  a 
flame  so  as  to  revivify  the  whole  body.  In  cold-blooded  ani- 
mals, this  irritability  of  ^he  heart  is  especially  remarkable. 


FIG.  88.— DIAGRAM  SHOWING  THE  POSITION  FIG.  39.  —  DIAGRAM  SHOWING  THE  POSITION 
OF  THE  VALVES  OF  THE  HEART  WHILE  OF  THE  VALVES  OF  THE  HEART  DITRING 
THE  WALLS  AKE  RELAXED  THE  CONTRACTION  OF  THE  VENTRICLES 

The  heart  of  a  turtle  will  pulsate,  and  the  blood  circulate  for  a 
week  after  its  head  has  been  cut  off ;  and  its  heart  will  throb 
regularly  many  hours  after  being  cut  out.  The  heart  of  a  frog 
or  serpent,  separated  entirely  from  the  body,  will  contract  at 
the  end  of  ten  or  twelve  hours ;  that  of  an  alligator  has  been 
known  to  beat  twenty-eight  hours  after  the  death  of  the 
animal. 

25.   Passage  of  the  Blood  through  the  Heart. — Let  us  now 
trace  the  course  of  the  blood  through  the  several  cavities  oi 

24.  Remarkable  property  of  the  tissue  of  the  heart  ?    How  shown  ?    How  interesting  ? 
In  cold-blooded  animals  ?    Heart  of  a  turtle  ?    Of  a  frog?    Alligator? 

25.  Course  of  the  blood  through  the  heart  1    Course  of  heart-currents  ? 


164  THE  CIRCULATION 

the  heart.  In  the  first  place,  the  venous  blood,  rendered  dark 
and  impure  by  contact  with  the  changing  tissues  of  the  body, 
returns  to  the  right  heart  by  the  veins.  It  enters  and  fills  the 
right  auricle  during  its  expansion ;  the  auricle  then  contracts 
and  fills  the  right  ventricle.  Almost  instantly,  the  ventricle 
contracts  forcibly  and  hurries  the  blood  along  the  great  artery 
of  the  lungs,  to  be  purified  in  those  organs.  Secondly,  having 
completed  the  circuit  of  the  lungs,  the  pure  and  bright  arterial 
blood  enters  the  left  auricle.  This  now  contracts  and  fills  the 
left  ventricle,  which  cavity,  in  its  turn,  contracts  and  sends  the 
blood  forth  on  its  journey  again  through  the  system.  This 
general  direction  from  right  to  left  is  the  uniform  and  undevi- 
ating  course  of  heart-currents. 

26.  The  mechanism  which  compels  this  regularity  is  as  sim- 
ple as  it  is  beautiful.     Each  ventricle  has  two  openings,  an 
inlet  and  an  outlet,  each  of  which  is  guarded  by  strong  cur- 
tains, or  valves.     These  valves  open  freely  to  admit  the  blood 
entering  from  the  right,  but  close  inflexibly  against  its  return. 
Thus,  when  the  auricle  contracts,  the  inlet  valve  opens ;  but  as 
soon  as  the  ventricle  begins  to  contract,  it  closes  promptly. 
The  contents  are  then,  so  to  speak,  cornered,  and  have  but  one 
avenue  of  escape  —  that  through  the   outlet  valve   into  the 
arteries  beyond.     As  soon  as  the  ventricle  begins  to  expand 
again,  this  valve  shuts  tightly  and  obstructs  the  passage.     The 
closing  of  these  valves  occasions  the  two  heart-sounds,  which 
we  hear  at  the  front  of  the  chest.     (Figs.  38,  39,  40,  and  41.) 

27.  Frequency  of  the  Heart's  Action. — The  alternation  of 
contraction  and  expansion  constitutes  the  heart-beats.     These 
follow  each  other  not  only  with  great  regularity,  but  with 
great  rapidity.     The  average  number  in  an  adult  man  is  about 
seventy-two  in  a  minute.      But   the   heart   is   a   susceptible 
organ,  and  many  circumstances  affect  its  rate  of  action.     Heat, 
exercise,  and  food  increase  its  action;  cold,  fasting,  and  sleep 
dimmish  it.     Posture,  too,  has  a  curious  influence ;  for  if  while 


26.  Openings  of  the  ventricles  ?    How  guarded  ?    How  do  the  valves  operate  ?    The 
consequence  ?    Heart-sounds  ? 

27.  Heart-beats  ?    The  heart  as  a  susceptible  organ  ?    Heat,  exercise,  etc.  ?    Posture  ? 


THE  CIRCULATION  165 

sitting  the  beats  of  the  heart  number  seventy-one,  standing 
erect  will  increase  them  to  eighty-one,  and  lying  down  will 
lower  them  to  sixty-six.  (Head  Note  8.) 

28.  The  modifying  influence  of  mental  emotions  is  very 
powerful.  Sudden  excitement  of  feeling  will  cause  the  heart  to 
palpitate,  or  throb  violently.  Depressing  emotions  sometimes 
temporarily  interrupt  its  movements,  and  the  person  faints  in 
consequence.  Extremes  o£  joy,  grief,  or  fear  have  occasionally 
suspended  the  heart's  action  entirely,  and  thus  caused  death. 
The  rate  of  the  heart-beat  may  be  naturally  above  or  below 
seventy-two.  Thus  it  is  stated  that  the  pulse  of  the  savage  is 
always  slower  than  that  of  the  civilized  man.  Bonaparte  and 
Wellington  were  very  much  alike  in  their  heart  pulsations, 
which  were  less  than  fifty  in  the  case  of  each.  (Head  Note  9.) 

7.  The  Heart  is  Injured  by  Over-exertion.  —  "  During  exertion,  if  the 
heart  is  not  oppressed,  its  movements,  though  rapid  and  forcible,  are  reg- 
ular and  equal.    But  when  it  becomes  embarrassed,  the  pulse-beats  are 
quick,  unequal,  and  at  last  become  irregular,  indicating  injury  to  the 
organ.    All  great  and  sudden  efforts  are  to  be  carefully  avoided ;  exces- 
sive exercise  often  produces  palpitation,  and  sometimes  enlargement  and 
valvular  disease  of  the  heart."  —  Huxley. 

"No  great  intellectual  thing  was  ever  done  by  great  effort;  a  great 
thing  can  only  be  done  by  a  great  man,  and  he  does  it  without  effort. 
The  body's  work  and  the  head's  work  are  to  be  done  quietly,  and  com- 
paratively without  effort.  Neither  limbs  or  brain  are  ever  to  be  strained 
to  their  utmost ;  that  is  not  the  way  in  which  the  greatest  quantity  of 
•work  is  to  be  got  out  of  them  ;  they  are  never  to  be  worked  furiously,  but 
with  tranquillity  and  constancy.  We  are  to  follow  the  plough  from  sunrise 
to  sunset,  but  not  to  pull  in  race-boats  at  the  twilight ;  we  shall  get  no 
fruit  of  that  kind  of  work  —  only  disease  of  the  heart."  —  Buskin. 

8.  Fainting.  —  "When  the  heart  suddenly  ceases  to  act,  fainting  or 
swooning  is  very  apt  to  take  place.    This  takes  place  for  the  reason  that 
the  brain  feels  most  speedily  the  lack  of  its  supply  of  blood.     Many  cir- 
cumstances may  cause  a  faint  —  such  as  a  fright,  joy,  excitement,  the 
sight  of  blood,  or  the  breathing  of  foul  air ;  or  it  may  be  due  to  disease 
of  the  heart.    In  some  persons,  fainting  becomes  a  kind  of  habit ;  they 
fall  into  a  fainting  fit  on  very  slight  agitation.     In  them  the  appearances 
are  much  worse  than  the  reality,  especially  to  those  who  are  not  familiar 
•with  the  ailment.    But  persons  who  faint  after  exhaustion,  fatigue,  fast- 
ing, or  anguish,  require  prompt  attention.    The  ordinary  signs  are  great 


28.  Mental  emotions?    Sadden  excitement?    Excessive  joy?    The  heart-beat  rate? 
Bonaparte  and  Wellington  ? 


166  THE  CIRCULATION 

29.  Activity  of  the  Heart.  —  The  average  number  of  heart- 
^eats  during  a  lifetime  may  be  considered  as  at  the  rate  of 
seventy-two  per  minute,  although  this  estimate  is  somewhat 
low,  for  during  several  years  of  early  life  the  rate  is  above  one 
hundred  a  minute.  In  one  hour,  then,  the  heart  pulsates  four 
thousand  times ;  in  a  day,  one  hundred  thousand  times ;  and 
in  a  year,  nearly  thirty-eight  million  times.  If  we  compute 
the  -number  during  a  lifetime  —  forty  years  being  the  present 
average  longevity  of  civilized  mankind  —  we  obtain  as  the  vast 
aggregate,  fifteen  hundred  millions  of  pulsations.  (Read  Note  10.) 

pallor,  loss  of  sensation,  and  trembling  of  the  limbs  and  loss  of  power 
over  the  muscles ;  the  breathing  and  pulse  go  on  imperfectly  or  stop. 
The  first  thing  to  do  is  to  place  the  head  low,  thus  favoring  the  supply  of 
blood  to  the  brain  ;  the  very  act  of  falling  is  often  sufficient  to  restore 
consciousness.  Water  may  be  sprinkled  on  the  face,  hartshorn  held  to 
the  nose,  or  mustard  over  the  heart.  Pure  air  is  a  great  restorative ; 
allow  a  current  of  fresh  air  to  flow  over  the  face,  and  loosen  any  tight 
bands  that  may  confine  the  chest."  — Dr.  J.  Knight  (in  part). 

9.  The  Heart  a  Vital  Machine.  —  "  The  heart  is  a  machine.  It  is  an 
organ  constructed  >of  muscular  chambers  and  communicating  passages, 
and  supplied  with  mechanical  contrivances,  adapted  to  guide  the  stream 
of  blood  passing  through  it,  and  to  prevent  a  reflux  in  the  backward 
direction.  Does  not  this  take  away  wonderfully  from  the  character  of 
fanciful  mystery  with  which  poets  and  sentimentalists  have  invested  it  ? 
The  heart  that  we  have  always  heard  of  as  the  centre  of  the  affections, 
the  home  of  sensibility,  the  dwelling-place  of  courage,  of  faith,  of  hope, 
and  all  the  rest  of  the  virtues,  is  after  all,  nothing  but  an  organ  to  serve 
for  the  impulsion  of  the  blood  —  a  mere  force-pump,  a  machine.  Does 
not  this  bring  down  our  ideas,  and  show  that  no  poetical  mystery  can 
escape  the  searching  investigation  of  the  anatomist  ?  Not  at  all. 

"For  this  machine  that  we  carry  about  with  us  in  our  breasts  is  alive. 
There,  at  its  post,  at  the  central  point  of  the  circulation,  with  the  soft 
lobes  of  the  lungs  folded  round  it  like  a  curtain,  it  contracts  and  relaxes, 
and  relaxes  and  contracts,  with  a  steady  and  unremitting  industry  that 
by  itself  is  something  worthy  of  our  admiration.  No  other  muscle  in  the 
body  can  do  this.  By  some  incomprehensible  vitality  of  its  own,  it  keeps 
up  its  rhythmical  contractions  without  the  aid  of  our  will  and  even  with- 
out our  knowledge.  While  you  are  asleep  and  while  you  are  awake,  from 
the  first  moment  of  your  birth,  even  from  before  your  birth,  up  to  the 
present  time,  it  has  never  for  one  moment  stopped  or  flagged  in  its  move- 
ments, for  if  it  were  to  do  so  death  would  be  the  result."  —  Dr.  J.  C. 
Dalton. 


Average  numbei  of  heart-beats  ?    In  oue  hour  ?    Year  ?    Lifetime  T 


THE  CIRCULATION  167 

30.  Again,  if  we  estimate  the  amount  of  blood  expelled  by 
each  contraction  of  the  ventricles  at  four  ounces,  then  the 
weight  of  the  blood  moved  during  one  minute  will  amount  to 
eighteen  pounds. ,   In  a  day  it  will  be  about  twelve  tons ;  in  a 
year,  four  thousand  tons ;  and  in  the  course  of  a  lifetime  over 
one  hundred  and  fifty  thousand  tons.     These  large  figures 
indicate,  in  some  measure,  the  immense  labor  necessary  to 
carry  on  the  interior  and  vital  operations  of  our  bodies.     In 
this  connection,  we  call  to  mind  the  fanciful  theories  of  the 
ancients  in  reference  to  the  uses  of  the  heart.     They  regarded 
it  as  the  abode  of  the  soul  and  the  source  of  the  nobler  emo- 
tions —  bravery,  generosity,  mercy,  and  love.     The  words  cour- 
age and  cordiality  are  derived  from  a  Latin  word  signifying 
heart.     Many  other  words  and  phrases,  as  hearty,  heart-felt,  to 
learn  by  heart,  and  large-hearted,  show  how  tenaciously  these 
exploded  opinions  have  fastened  themselves  upon  our  language. 

31.  At  the  present  time,  the  tendency  is  to  ascribe  purely 
mechanical  functions  to  the  heart.     This  view,  like  the  older 
one,  is  inadequate  y  for  it  expresses  only  a  small  part  of  our 
knowledge  of  this  organ.     The  heart  is  unlike  a  simple  ma- 
chine, because  its  motive  power  is  not  applied  from  without, 
but  resides  in  its  own  substance.     Moreover,  it  repairs  its  own 
waste,  it  lubricates  its  own  action,  and  it  modifies  its  move- 
ments according  to  the  varying  needs  of  the  system.     It  is 
more  than  a  mere  force-pump,  just  as  the  stomach  is  something 
more  than  a  crucible,  and  the  eye  something  more  than  an 
optical  instrument.     (Read  Note  11.) 

32.  The  Arteries. — The  tube-like  canals  which  carry  the 
blood  away  from  the  heart  are  the  arteries.     Their  walls  are 

10.  The  Heart.  —  "  You  all  know  where  it  is.  It  is  the  most  wonder- 
ful little  pump  in  the  world.  There  is  no  steam-engine  half  so  clever  at 
its  work,  or  so  strong.  There  it  is,  in  every  one  of  us,  beat,  beating  —  all 
day  and  all  night,  year  after  year,  never  stopping,  like  a  watch  ticking ; 
only  it  never  needs  to  be  wound  up,  —  God  winds  it  up  once  for  all."  — 
Author  of  "  Bab  and  His  Friends." 


80.  Amount  of  blood  expelled  ?    Theories  of  the  ancients  ? 

81.  The  tendency  at  the  present  time  ?    Why  is  this  view  inadequate  f 

82.  What  are  the  arteries  ?    Their  walls  ?    Their  membrane  ? 


.  168  THE  CIRCULATION 

made  of  tough,  fibrous  materials,  so  that  they  sustain  the  mighty 
impulse  of  the  heart,  and  are  not  ruptured.  In  common  with 
the  heart,  the  arteries  have  a  delicately  smooth  lining  mem- 
brane. They  are  also  elastic,  and  thus  re-enforce  the  action 
of  the  heart;  they  always  remain  open  when  cut  across,  and 
after  death  are  usually  found  empty. 

33.  The  early  anatomists  observed  this  condition,  and  sup- 
posing that  it  existed  during  life,  came  to  the  conclusion  that 
these  tubes    were  designed  to  act  as  air-vessels  —  hence  the 
name  artery,  from  Greek  words  which  signify  "  containing  air." 
This  circumstance  affords  us  an  illustration  of  the  mistaken 
notions  of  the  ancients  in  reference  to  the  internal  operations 
of  the  body.     Cicero  speaks  of  the  arteries  as  "  conveying  the 
breath  to  all  parts  of  the  body.'7 

34.  The  arterial  system  springs  from  the  heart  by  a  single 
trunk,  like  a  minute  and  hollow  tree,  with  numberless  branches. 
As  these  branches  leave  the  heart,  they  divide  and  subdivide, 
continually  growing  smaller  and  smaller,   until  they  can  no 
longer  be  traced  by  the  naked  eye.     If,  then,  we  continue  the 
examination  by  the  aid  of  a  microscope,  we  see  these  small 
branches  sending  off  still  smaller  ones,  until  all  the  organs  of 
the  body  are  penetrated  by  arteries. 

35.  Histology  of  the  Arteries.  — The  arteries  have'  three  prin- 
cipal coats.     An  inner,  or  epithelial  coat;  a  middle  coat  con- 
taining elastic  fibrous  tissue,  and  unstriped  muscular  fibres 
arranged  transversely  around  the  vessel ;  and  an  external  coat 
of  condensed  connective  tissue.     The  principal  difference  be- 
tween the  -larger  and  smaller  arteries  is  in  the  structure  of 
their  middle  coat.     In  the  smaller  arteries  this  is  composed 
exclusively  of  muscular  fibres.     In  arteries  of  medium  size  it 
contains  both  muscular  and  elastic  tissue,  whilst  in  those  of 
the  largest  calibre  it  consists  of  elastic  tissue  only ;  therefore, 
the  large  arteries  possess  much  elasticity  and   but  little  con- 
tractility, while  in  the  smaller  these  conditions  are  reversed. 

33.  Early  anatomists  ?    The  service  of  the  illustration  ? 

34.  The  arterial  system  ?    The  branches  and  sub-branches  of  the  arteries  ? 

85.  What  are  the  three  principal  coats  of  the  arteries  ?    The  principal  difference  between 
the  larger  and  smaller  arteries  ? 


THE  CIRCULATION  169 

36.  The  Pulse.  —  With  each  contraction  of  the  left  side  of 
the  heart,  the  impulse  causes  a  wave-like  motion  to  traverse 
the  entire  arterial  system.     If  the  arteries  were  exposed  to 
view,  we  might  see  successive  waves  speeding  from  the  heart 
to  tlifli  smallest  of  the  branches.     The  general  course  of  the  ar- 
teries is  as  far  as  possible  from  the  surface.    This  arrangement 
is  certainly  wise,  as  it  renders  them  less  liable  to  injury — the 
wounding  of  an  artery  being  especially  dangerous.     It  also 
protects  the  arteries  from  external  and  unequal  pressure,  by 
which  the  force  of  the  heart  would  be  counteracted  and  wasted. 
Accordingly,  we  generally  find  these  vessels  close  to  the  bones, 
or  hiding  behind  the  muscles  and  within  the  cavities  of  the 
body. 

37.  In  a  few  situations,  however,  the  arteries  lie  near  the 
surface;  and  if  we  apply  the  finger  to  any  of  these  parts, 
we  shall  distinctly  feel  a  throbbing  motion  taking  place  in 
harmony  with  the  heart-beat.    This  is  part  of  the  wave-motion 
just  mentioned,  and  is  known  as  the  pulse.     All  are  familiar 
with  the  pulse  at  the  wrist,  in  the  radial  artery ;  but  it  is  not 
peculiar  to  that  position,  for  it  may  be  felt  in  the  carotid  of 
the  neck,  in  the  temporal  at  the  temple,  and  elsewhere,  espe- 
cially near  the  joints. 

38.  Since  the  heart-beat  makes  the  pulse,  whatever  affects 
the  former  affects  the  latter  also.    Accordingly,  the  pulse  is 


FIG.  42.  — THK  FORM  OF  THE  PULSB 

a  good  index  of  the  state  of  the  heajth,  so  far  as  the  health 
depends  upon  the  action  of  the  heart.     It  informs  the  physi- 

11.   The  Beating  of  the  Pulse.  —  "According  to  experiments  made  in 
Paris,  the  pulse  of  a  lion  beats  forty  times  a  minute ;  that  of  a  tiger, 


86.  Successive  undulations  from  the  heart  ?    Course  of  the  arteries  ?    Protection  of  the 
arteries  ?    General  location  of  the  arteries  ? 

37.  Where  do  the  arteries  lie  ?    If  we  apply  the  finger  ?    Pulse?    Where  felt? 


170  THE  CIRCULATION 

cian  of  the  condition  of  the  circulation  in  four  particulars 
—  its  rate,  regularity,  force,  and  fulness ;  and  nearly  every 
disease  modifies  in  some  respect  the  condition  of  the  pulse. 
A  very  ingenious  instrument,  known  as  the  sphygmograph,  or 
pulse-writer,  has  recently  been  invented,  by  the  aid  of  which 
the  pulse  is  made  to  write  upon  paper  its  own  signature,  or 
rather  to  sketch  its  own  profile.  This  instrument  shows  with 
great  accuracy  the  difference  between  the  pulses  of  health  and 
those  of  disease.  In  Fig.  42  is  traced  the  form  of  the  pulse  in 
health,  which  should  be  read  from  left  to  right.  That  part  of 
the  trace  which  is  nearly  perpendicular  coincides  with  the 
contraction  of  the  ventricles,  while  the  wavy  portion  marks 
their  dilatation.  (Bead  Note  12.) 

39.  The  Veins.  —  The  vessels  by  which  the  blood  returns  to 
the  heart  are  called  veins.  They,  like  the  arteries,  contain 
three  coats,  —  inner,  middle,  and  exterior.  They  are  largely, 
however,  composed  of  condensed  connective  tissue,  and  contain 
a  much  smaller  quantity  of  muscular  and  elastic  fibres.  They 
are  consequently  more  flaccid  and  compressible  than  the 
arteries,  and  are  less  elastic  and  contractile.  At  first  they 
are  extremely  small;  but  uniting  together  as  they  advance, 
they  constantly  increase  in  size,  reminding  us  of  the  way  in 
which  the  fine  rootlets  of  the  plant  join  together  to  form  the 
large  roots,  or  of  the  rills  and  rivulets  that  flow  together  to 
form  the  large  streams  and  rivers.  In  structure,  the  veins 
resemble  the  arteries,  but  their  walls  are  comparatively  in- 
elastic. They  are  more  numerous  and  communicate  with 
each  other  freely  in  their  course  by  means  of  interlacing 
branches. 

ninety-six  times  ;  of  a  tapir,  forty -four  times ;  of  a  horse,  forty  times  ;  of 
a  wolf,  forty-five  times  ;  of  a  fox,  forty-three  times  ;  of  a  bear,  thirty- 
eight  times ;  of  a  monkey,  forty-eight  times  ;  of  an  eagle,  one  hundred 
and*  sixty  times.  It  was  impossible  to  determine  the  beatings  of  the 
elephant's  pulse.  A  butterfly,  however,  it  was  discovered,  experienced 
sixty  heart  pulsations  in  a  minute." 


88.  The  pulse  as  an  index  f    Of  what  does  it  inform  the  physician  ?    Instrument  for 
recording  pulsation  ? 

89.  What  are  the  veins  2    £o«  do  they  form  ?    What  do  they  resemble  ? 


THE  CIRCULATION 


171 


40.  But  the  chief  point  of  distinction  is  in  the  presence  of 
the  valves  in  the  veins.  These  are  little  folds  of  membrane, 
disposed  in  such  a  way  that  they  open  only  to  receive  the 
blood  flowing  toward  the  heart,  and  close  against  a  current  in 
the  opposite  direction.  Their  position  in  the  veins  on  the  back 
of  the  hand  may  be  readily  observed,  if  we  first  obstruct  the 
return  of  blood  by  a  cord  tied  around  the  forearm  or  wrist. 


FIG.  43.  —  VEIN  WITH  VALVES 
OPEN 


FIG.  44.  —  VEIN  WITH  VALVES  CLOSED  ; 
THE  STREAM  OF  BLOOD  PASSING  OFF 
BY  A  LATERAL  BRANCH 


fn  a  few  moments  the  veins  will  appear  swollen,  and  upon 
them  will  be  seen  certain  prominences,  about  an  inch  apart. 
These  latter  indicate  the  location  of  the  valves,  or,  rather,  they 
show  that  the  vessels  in  front  of  the  valves  are  distended  by 
the  blood,  which  cannot  force  a  passage  back  through  them. 

41.  This  simple  experiment  proves  that  the  true  direction 
of  the  venous  blood  is  toward  the  heart.  That  the  color  of  the 
blood  is  dark  will  be  evident,  if  we  compare  the  hand  thus 
bound  by  a  cord  with  the  hand  not  so  bound.  It  also  proves 
that  the  veins  lie  near  the  surface,  while  the  arteries  are 


40.  Valves  in  the  veins  ?    What  are  they  ?    Their  position  ?    Experiment  with  the  cord  ? 

41.  What  will  be  proved  by  the  experiment  ?    What  inference  is  drawn  ? 


172  THE  CIRCULATION 

beneath  the  muscles,  well  protected  from  pressure ;  and  that 
free  communication  exists  from  one  vein  to  another.  If  now 
we  test  the  temperature  of  the  constricted  member  by  means 
of  a  thermometer,  we  will  find  that  it  is  colder  than  natural, 
although  the  amount  of  blood  is  larger  than  usual.  From  this 
fact  we  infer,  that  whatever  impedes  the  venous  circulation 
tends  to  diminish  vitality;  and  hence,  articles  of  clothing  or 
constrained  postures,  that  hinder  the  circulation  of  the  blood, 
are  to  be  avoided  as  injurious  to  the  health. 

42.  The  Capillaries.  —  A  third  set  of  vessels  completes  the 
list  of  the  organs  of  circulation,  namely,  the  capillary  vessels, 
so  called  (from  the  Latin  word  capittaris,  hair-like),  because  of 
their  extreme  fineness.     They  are,  however,  smaller  than  any 
hair,  having  a  diameter  of  about  y-^-g-  of  an  inch,  and  can  only 
be  observed  by  the  use  of  the  microscope.     These  vessels  are 
the  connecting  link  between  the  last  of  the  arteries  and  the 
first  of  the  veins.    The  existence  of  these  vessels  was  unknown 
to  Harvey,  and  was  the  one  step  wanting  to  complete  his  great 
discovery.     The  capillaries  were  not  discovered  until  1661. 

43.  The  flow  of  blood  through  the  veins  is  dependent  upon 
three  different  forces.     First,  the  pressure  from  the  capillary 
circulation,  second,  the  contraction  of  the  muscles,  and  third, 
the  respiration.     The  pressure  from  the  capillaries  is  the  re- 
maining impulse  originally  derived  from  the  heart,  and  as  the 
capillary  veins  increase  in  size,  from  the  capillaries  toward  the 
larger  veins,  the  flow  is  naturally  facilitated.     The  action  of 
the  muscles  is  exerted  through  their  contraction.     The  veins 
in  the  arms  and  legs,  as  well  as  in  most  parts  of  the  body,  lie 
between  the  muscles,  so  that  each  contraction  of  the  latter 
squeezes  the  blood  out  of  the  veins  and  forward  toward  the 
heart,  the  valves  in  them  preventing  any  flow  the  other  way. 
The  force  exerted  through  the  respiration  is  during  the  act  of 
inspiration.     At  this  time  the  chest  expands  and  enlarges  in 
all  directions,  allowing  the  veins  of  the  thorax  to  fill  more 
readily,  and  thus  making  room  for  the  blood  in  the  veins  of 
other  parts  of  the  body.     (Head  Note  13.) 

42.  Capillaries  f    How  regarded  ?    Harvey  ? 

43.  On  what  three  forces  ie  the  flow  of  blood  dependent  ?    Describe  them. 


THE  CIRCULATION 


173 


44.  The  circulation  of  the  blood,  as  seen  under  the  micro- 
scope, in  the  transparent  web  of  a  frog's  foot,  is  a  beautiful 
sight,  possessing  more  than  ordinary  interest,  from  the  fact 
that  something  much  grander  is  taking  place  in  our  own  bodies. 
It  is  like  opening  a  secret  page  in  the  history  of  our  own 
frames.  We  there  see  distinctly  the  three  classes  of  vessels 
with  their  moving  contents ;  first,  the  artery,  with  its  torrent  of 
blood  rushing  down  from^the  heart;  secondly,  the  vein,  with 
its  slow,  steady  stream  flowing  in  the  opposite  direction ;  and 


FIG.  45.  — WEB  OF  A  FBOQ'S  FOOT, 
slightly  magnified 


Fw.  46.  —  MARGIN  or  FBOG'S  WIB, 
magnified  thirty  diameters 


between  them  lies  the  network  of  capillaries,  so  fine  that  the 
corpuscles  can  pass  through  only  "  in  single  file."  The  current 
of  the  capillaries  has  here  an  uncertain  or  swaying  motion, 
hurrying  first  in  one  direction,  then  hesitating,  and  turning 
back  in  the  opposite  direction,  and  sometimes  the  capillaries 
contract  so  as  to  be  entirely  empty.  Certain  of  the  tissues  are 
destitute  of  capillaries;  such  are  cartilage,  hair,  and  a  few 
others  on  the  exterior  of  the  body.  In  all  other  structures, 
networks  of  these  vessels  are  spread  out  in  countless  numbers ; 
so  abundant  is  the  supply,  that  it  is  almost  impossible  to 
puncture  any  part  with  the  point  of  a  needle  without  lacerat- 


44.  The  circulation  of  the  blood  in  the  web  of  a  frog's  foot  ?    Describe  it.    How  general 
is  the  existence  of  the  tissues  ? 


174  THE  CIRCULATION 

ing  tens,  or  even  hundreds  of  these  vessels.     (Head  Notes  12 
and  13.) 

45.  The  capillaries  are  elastic,  and  may  so  expand  as  to  pro- 
duce an  effect  visible  to  the  naked  eye.  If  a  grain  of  sand,  or 
some  other  foreign  particle,  lodge  in  the  eye,  it  will  become 
irritated,  and  in  a  short  time  the  white  of  the  eye  will  be 
"  blood-shot."  This  appearance  is  due  to  an  increase  in  the 
size  of  these  vessels.  A  blush  is  another  example  of  this,  but 
the  excitement  comes  throiigh  the  nervous  system,  and  the 
cause  is  some  transient  emotion,  either  of  pleasure  or  pain. 
Another  example  is  sometimes  seen  in  purplish  faces  of  men 

12.  Course  of  the  Blood  in  the  Capillaries.  —  "The  phenomena  of 
the  capillary  circulation  are  only  observable  with  the  aid  of  the  micro- 
scope.   It  was  not  granted  to  the  discoverer  of  the  circulation  to  see  the 
blood  moving  through  the  capillaries,  and  he  never  knew  the  exact  mode 
of  communication  between  the  arteries  and  veins.    After  it  was  pretty 
generally  acknowledged  that  the  blood  did  pass  from  the  arteries  to  the 
veins,  it  was  disputed  whether  it  passed  in  an  intermediate  system  of  ves- 
sels, or  became  diffused  in  the  substance  of  the  tissues,  like  a  river  flow- 
ing between  numberless  little  islands,  to  be  collected    by  the  venous 
radicles  and  conveyed  to  the  heart.     Accurate  microscopic  investigations 
have  now  demonstrated  the  existence,  and  given  us  a  clear  idea  of  the 
anatomy,  of  the  intermediate  vessels.     In  1661  the  celebrated  anatomist 
Malpighi  first  saw  the  movement  of  the  blood  in  the  capillaries,  in  the 
lungs  of  a  frog.    This  spectacle  has  ever  since  been  the  delight  of  the 
physiologist.     We  see  the  great  arterial  rivers,  in  which  the  blood  flows 
with  wonderful  rapidity,  branching  and  subdividing,  until  the  blood  is 
brought  to  the  superb  network  of  fine  capillaries,  where  the  corpuscles 
dart  along  one  by  one,  the  fluid  then  being  collected  by  the  veins,  and 
carried  in  great  currents  to  the  heart."  —  Flint. 

13.  Experiment.    Circulation.  —  The  circulation  of  the  blood  can  be 
fairly  well  illustrated  by  the  aid  of  a  "Davidson  "  syringe,  some  rubber 
tubing,  and  a  piece  of  glass  tubing. 

The  bulb  of  the  syringe  represents  the  heart,  the  elastic  tubing  the 
arteries,  and  the  fine  glass  tubing  the  capillaries. 

Attach  the  rubber  tubing  to  the  smallest  nozzle  of  the  syringe  (the 
tubing  should  be  highly  elastic,  the  black  kind  is  the  best ;  it  should  be 
about  one-fourth  inch  diameter),  place  the  other  end  of  the  syringe  in  a 
vessel  filled  with  water. 

Upon  compressing  the  bulb  of  the  syringe,  the  water  will  be  seen  to 
issue  from  the  tubing  in  jets  corresponding  with  the  compressions  of  the 
bulb,  but  a  little  retarded ;  placing  the  finger  on  the  tubing  but  little 


45.  Elasticity  of  the  capillaries  ?    Grain  of  sand  in  the  eye  ?    Blush  ?    Other  cases  ? 


THE  CIRCULATION  175 

addicted  to  drinking  brandy ;  in  them  the  condition  is  a  con- 
gestion of  the  capillary  circulation,  and  is  permanent,  the  ves- 
sels having  lost  their  power  of  elastic  contraction. 

46.  Rapidity  of  the  Circulation.  —  That  the  blood  moves  with 
great  rapidity  is  evident  from  the  almost  instant  effects  of  cer- 
tain poisons,  as  prussic  acid,  which  act  through  the  blood. 
Experiments  upon  the  horse,  dog,  and  other  inferior  animals, 
have  been  made  to  measure  its  velocity.  If  a  substance  which 

expansion  will  be  felt.  Now  into  the  rubber  tube  insert  the  glass  tube, 
which  should  be  about  two  feet  long  and  be  drawn  out  to  a  fine  point. 
Compressing  again  the  bulb  of  the  syringe,  the  water  will  be  seen  to  issue 
from  the  glass  point  in  a  continuous  stream,  and  not  hi  an  interrupted 
one,  as  from  the  rubber  end. 

The  explanation  of  this  is  as  follows :  During  each  compression  of  the 
bulb,  the  water  expands  the  rubber  tubing  because  its  outflow  is  con- 
siderably lessened  by  the  resistance  of  the  unyielding  glass  tube  and  its 
much-narrowed  end,  and  during  the  interval  of  two  compressions,  during 
which  the  bulb  fills  again,  the  rubber  tubing  contracts  upon  its  contents 
and  slowly  expels  it.  If  now  the  compressions  of  the  bulb  are  so  timed 
that  the  rubber  tubing  is  kept  stretched,  the  flow  from  the  glass-end  will 
be  continuous.  The  finger  on  the  tubing xwill  now  feel  each  stroke  of  the 
syringe  in  the  decided  expansion  of  the  rubber. 

Applied  to  the  circulation  of  the  blood,  this  experiment  shows  the 
following : 

The  power  of  the  hand  together  with  the  bulb  of  the  syringe  represent 
the  heart,  which,  with  each  contraction,  sends  its  contents  forth  into  the 
arteries.  These  are  well  represented  by  the  elastic  tubing,  as  they,  jn 
reality,  are  nothing  more  than  that.  During  the  systole  of  the  heart 
(the  compression  of  the  bulb),  they  are  distended  to  their  full  capacity ; 
during  the  diastole  of  the  heart  (represented  by  the  passive  filling  of  the 
bulb),  they  contract  upon  their  contents  and  send  it  forward  toward  the 
capillaries  and  veins.  The  latter  are  represented  by  the  glass  tubing, 
from  which  we  have  seen  the  water  issue  in  a  cortinuous  stream.  In  the 
capillaries  and  veins  the  blood  flows  in  a  continuous  stream,  due  to  the 
fact  that  the  force  of  the  heart's  action  is  gradually  lost  in  expanding 
the  arteries,  and  is  felt  less  and  less  the  farther  they  are  removed  from 
the  heart ;  the  arteries  becoming  smaller  and  smaller,  the  intermittency 
of  the  flow  is  lost  when  the  capillaries  are  reached. 

The  expansion  which  the  finger  feels  when  placed  upon  the  rubber 
tubing  represents  the  pulse,  which  is  the  maximum  distension  of  the 
artery  at  that  point. 

46.  Show  what  time  is  required  for  a  given  portion  of  blood  to  travel  oueefarbund  the 
body.  S  *  ^ 

I  UNIVERSIT 


176  THE  CIRCULATION 

is  capable  of  a  distinct  chemical  reaction  (as  potassium  ferro- 
cyanide,  or  barium  nitrate)  be  introduced  into  a  vein  on  one 
side  of  a  horse,  and  at  the  end  of  twenty  or  thirty-two  seconds 
blood  be  taken  from  a  distant  vein  on  the  other  side,  its 
presence  may  be  detected.  In  man,  the  blood  moves  with 
greater  speed,  and  the  circuit  is  completed  in  twenty-four 
seconds. 

47.  What  length  of  time  is  required  for  all  the  blood  of  the 
body  to  make  a  complete   round   of  the   circulation?     This 
question  cannot  be  answered  with  absolute  accuracy,  since  the 
amount  of  the  blood  is  subject  to  continual  variations.     But, 
if  we  assume  this  to  be  one-eighth  of  the  weight  of  the  body  — 
about  eighteen  pounds  —  it  will  be  sufficiently  correct  for  our 
purpose.     Now  to  complete  the  circuit,  this  blood  must  pass 
once  through  the  left  ventricle,  the  capacity  of  which  is  two 
ounces.     Accordingly,  we   find   that,   under   ordinary  circum- 
stances, all  the  blood  makes  one  complete  rotation  every  two 
minutes  —  passing  successively  through  the  heart,  the  capil- 
laries of  the  lungs,  the  arteries,  the  capillaries  ef  the  extremi- 
ties, and  through  the  veins. 

48.  That  portion  of  the  blood  which  passes  through  the 
spleen,  pancreas,  stomach,  and  intestines  differs  from  the  rest 
of  the  blood  in  that  it  has  to  pass  through  the  liver.     This  is 
known  as  the  portal  division,  while  that  passing  through  the 
lungs  is  the  pulmonary  division,  and  that  through  the  rest  of 
the  body  the  systemic  division.     All  the  blood  coming  from 
the  organs  above  enumerated  is  collected  by  the  veins,, which 
unite  to  form  what  is  called  the  portal  vein.     From  here  the 
blood,  filled  with  all  the  products  of  digestion,  passes  through 
the  cells  of  the  liver,  where  all  the  glucose  is  abstracted  from 
the  blood  and  stored  up  as  glycogen.     The  blood  is  then  col- 
lected in  a  second  set  of  capillaries,  which  go  to  form  the 
hepatic   vein;    and   this   in  turn   conveys   the   blood   to   the 
inferior  vena  cava,  and  so  on  to  the  right  auricle.     The  liver 
itself  is  nourished  by  fresh  arterial  blood  through  the  hepatic 

47.  Time  required  for  all  the  blood  in  the  body  to  circulate  completely  around  ? 

48.  What  can  you  say  of  the  blood  which  passes  through  the  li ver  ? 


THE  CIRCULATION  177 

artery,  which  blood,  after  it  has  passed  through  the  capillaries, 
mingles  with  the  blood  of  the  portal  capillaries,  and  is  by  them 
returned  to  the  heart  through  the  hepatic  vein. 

49.  Assimilation.  —  The  crowning  act  of  the  circulation  — 
the  furnishing  of  supplies  to  the  different  parts  of  the  body  — 
is  effected  by  means  of  the  capillaries.     The  organs  have  been 
wasted  by  use ;  the  blood  has  been  enriched  by  the  products 
of  digestion.     Here,  within  the  meshes  of  the  capillary  net- 
work, the  needy  tissues  and  the  needed  nutriment  are  brought 
together.     By  some  mysterious  chemistry,  each  tissue  selects 
and  withdraws  from  the  blood  the  materials  it  requires,  and 
converts  them  into  a  substance  like  itself.     This  conversion 
of  lifeless  food  into  living  tissue  is  called  assimilation.     The 
process  probably  takes  place  at  all  times,  but  the  period  espe- 
cially favorable  for  it  is  during  sleep.     Then  the  circulation  is 
slower  and  more   regular,  and  most  of  the  functions  are  at 
rest.     The  body  is  then  like  some  trusty  ship,  which,  after  a 
long  vogage,  is  "  hauled  up  for  repairs."     {Read  Note  14.) 

50.  Lymph  and  the  Lymphatic  System.  —  As  the  blood  circu- 
lates through  the  capillaries  of  the  body,  a  good  deal  of  its 
liquid  portion,  the  plasma,  passes  through  the  walls  of  the 
capillaries  into  the  surrounding  tissue  cells.     This  plasma  is 

14.  Assimilation  in  Repair.  — "  Most  animals  have  the  power  to 
repair,  to  a  greater  or  less  extent,  the  mutilations  they  undergo.  In 
man,  if  the  skin  is  torn  off,  a  new  skin  heals  over  the  injury,  and  a  broken 
bone  is  caused  to  re-unite  by  the  deposit  of  bone  tissue  between  the  frag- 
ments. But  among  the  lower  animals  this  power  is  carried  to  a  high 
degree.  The  tail  of  a  lizard,  if  cut  off,  will  quickly  form  anew,  although 
of  a  complex  structure  ;  and  spiders  and  crabs  are  able  to  develop  new 
claws  upon  the  stumps  of  broken  ones.  Observations  made  on  salaman- 
ders, or  water-lizards,  show  the  still  more  remarkable  fact  that  the  eye 
and  a  part  of  the  head  may  be  entirely  restored.  Certain  kinds  of  earth- 
worms can  reproduce  a  large  portion  of  their  bodies,  and  any  fragment  of 
the  hydra  is  able  to  restore  itself,  and  become  a  complete  creature  after  its 
kind.  Assimilation  is  especially  active  in  early  years,  while  the  body  is 
growing;  for  this  reason,  among  others,  the  perfect  health  of  children 
requires  that  they  shall  give  a  greater  number  of  hours  to  sleep  —  deep, 
regular,  and  undisturbed  sleep  —  than  is  needed  in  later  life."  —  Milne 
Edwards.  ,  

49.  What  is  stated  of  the  injuries  to  the  blood-vessels  ? 
60.   How  does  alcohol  affect  the  heart's  action  ? 


178  THE  CIRCULATION 

here  called  lymph,  and  conveys  nourishment  to  the  cells ;  the 
latter  being  bathed  constantly  by  the  lymph,  extract  therefrom 
what  they  require  for  nourishment,  and  excrete  into  it  their 
waste  materials.  The  lymphatic  system  begins  in  irregular 
spaces  between  the  cells,  which  gradually  unite  to  form  small 
Jymph  capillaries,. which  gradually  increase  and  unite  to  form 
larger  and  larger  vessels,  which  finally  end  in  the  large  thoracic 
duct.  This  duct  ascends  through  the  abdomen  and  chest  to 
the  root  of  the  neck,  where  it  is  joined  by  lymphatics  from  the 
left  side  of  the  head  and  the  left  upper  extremity,  and  empties 
itself  into  the  left  subclavian  vein. 

51.  The  lymphatic  vessels  from  the  right  side  of  the  head  and 
neck,  and  the  right  upper  extremity,  form  the  right  lymphatic 
duct  which  terminates  in  the  right  subclavian  vein.     Thus  the 
lymph  collected  from  the  tissues  of  the  entire  body  is  mingled 
with  the  venous  blood  a  little  before  its  arrival  at  the  right  side 
of  the  heart.   Along  the  course  of  the  lymphatic  vessels  through- 
out the  body  are  found  numerous   glands,  called  lymphatic 
glands,  through  which  the  lymph  percolates  in  its  flow  toward 
the   heart.     The   function   of   these   glands  is  not   definitely 
known,  but  they  are  supposed  to  produce  the  white  globules 
of  the   blood,  as   they  contain   numerous   cells   in  structure 
and  appearance  identical  to  them.     The  lymphatic  vessels  are 
supplied  with  numerous  valves,  in  structure  like  those  of  the 
veins,  and  the  flow  of  lymph  through  the  lymphatic  system  is 
dependent  upon  the  same   causes  which   govern  the   flow  of 
blood  through  the  veins. 

52.  Injuries  to  the  Blood-vessels.  —  It  is  important  for  us  to 
be  able  to  discriminate  between  an  artery  and  a  vein,  in  the 
case  of  a  wound,  and  if  we  remember  the  physiology  of  the 
circulation  we  may  readily  do  so.     For,  as  we  have  already 
seen,  hemorrhage  from  an  artery  is  much  more  dangerous  than 
that  from  a  vein.     The  latter  tends  to  cease  spontaneously 
after  a  short  time.     The  arterial  blood  flows  away  from  the 
heart  with  considerable  force,  in  jets,  and  its  color  is  bright 

51.   Describe  the  right  lymphatic  duet. 

62.  What  is  stated  of  the  injuries  to  the  blood-vessels  ? 


THE  CIRCULATION  179 

scarlet.  The  venous  blood  flows  toward  the  heart  from  that 
side  of  the  wound  farthest  from  the  heart,  its  stream  being 
continuous  and  sluggish;  its  color  is  dark.  In  an  injury  to 
an  artery,  pressure  should  be  made  between  the  heart  and  the 
wound,  while,  in  the  case  of  a  vein  that  persistently  bleeds,  it 
should  be  made  upon  the  vessel  beyond  its  point  of  injury. 

53.  Effects  of  Alcohol  upon  the  Heart.  —  The  first  symptoms 
after  a  moderate  dose  o£.  alcohol  is  an  increase  of  the  heart's 
action,  a  flushing  of  the  face,  a  sensation  of  warmth  within,  a 
general  glow  without,  and  some  other  appearances  of  increased 
vitality.     The  action.has  been  that  of  a  spur  or  goad.     It  has 
caused  strength  to  be  expended  instead  of  increasing  it,  and, 
in  fact,  costs  the  system  whatever  amount  of  force  is  neces- 
sary to  expel  it;  so  that  there  is  a  loss  of  strength,  and  not 
a  gain. 

54.  The  late  Dr.  Parkes  made  a  careful  study  of  the  amount 
of  strain  put  upon  the  heart  by  alcohol.     He  found  that  it 
increased  both  the  number  and  force  of  the  heart's  pulsations. 
The  period  of  rest  between  the  beats  is  reduced,  and,  conse- 
quently, the  heart's  nutrition  must  be  interfered  with.     He 
estimates,  in  one  set  of  experiments,  that  the  extra  work  of 
the  heart,  induced  by  alcohol,  was  equivalent  to  the  lifting  of 
15.8  tons  one  foot  daily ;  and  during  two  days,  24  tons  in  excess 
of  the  regular  work.     Another  experimenter  states  that  he  has 
known  a  single  glass  of  liquor  to  cause  8000  extra  heart-beats, 
equivalent  to  the  unnecessary  lifting  of  9  tons  the  distance  of 
one  foot.     Estimated  in  another  way,  this  amount  of  overtax 
of  the  heart  is  equal  to  that  which  takes  place,  during  one  day, 
in  a  person  having  a  fever  that  raises  the  pulse  six  to  nine 
beats  above  the  rate  of  health. 

55.  Alcohol  as  a  Fat  Producer.  —  Alcohol  is  said  to  diminish 
waste,  and  to  make  those  "  fleshy  "  who  use  it.    This  may  well 
be  the  case  in  those  —  and  the  proportion  is  not  small  —  who 
are  rendered  sluggish  and  sleepy  by  it.     The  fat  which  they 
acquire  is  the  fat  of  inaction.     If  we  may  judge  of  the  true 

53.  How  does  alcohol  effect  the  heart's  action  ? 

54.  Describe  Dr.  Parke's  experiment. 


180  THE  CIRCULATION 

influence  of  alcohol  by  experiments  on  the  lower  animals,  that 
are  compelled  to  take  it  pure,  we  will  not  grant  it  any  fattening 
power. 

56.  There  is  a  certain  "fatty  degeneration"  in  man  —  the 
result  of  alcohol  drinking  —  that  is  very  disastrous,  namely,  a 
deposit  of  fat  in  the  muscles  of  the  body.     This  is  destructive 
or  weakening  to  muscular  power,  and  when  it  evinces  itself  in 
the  heart,  it  creates  a  change  that  is  to  be  dreaded  as  sapping 
the  strength  of  the  one  particular  organ  that  should  be  strong 
in  drinkers.     It  attacks  them  at  a  vital  spot.     The  blood  also 
undergoes  a  fatty  change  which  greatly,  impairs  its  work  of 
nourishing  the  body. 

57.  Exhaustion  Due  to  Alcohol.  —  The  heart  does  not  become 
habituated  to  the  poison  nor  become  tolerant  of  it.     On  the 
contrary,  it  is  set  moving,  with  this  abnormal  activity,  with 
each  renewal  of  the  dose.     This  form  of  exertion  is  not  exer- 
cise, it  is  overwork ;  it  is  not  strengthening,  it  is  exhausting. 
Very  few  persons  who  habitually  use  alcoholic  stimulants  are 
aware  of  the  enormous  strain  that  is  imposed  upon  the  heart, 
although  to  those  who  studiously  consider  the   matter  the 
wonder  is  that  this  organ  is  not  more  rapidly  worn  out  than 
it  is.     If  it  were  not  for  the  fact  that  the  heart  is  made  of  the 
strongest  muscular  tissue  in  the  body,  it  would  of  necessity 
fail  from  overstrain  long  before  it  does. 

58.  The  condition  of  the  heart,  mentioned  in  the  last  section, 
is  known  to  physicians  as  "  fatty  heart,"  and  in  part  explains 
why  it  is  that  drunkards  are  so  little  able  to  withstand  the 
attack  of  those  .diseases  which  are  attended  by  fever.     It  is  a 
well-known  fact  that  they  are  among  the  first  to  succumb  to 
cholera  and  other  epidemic  diseases.     Sunstroke  is  another 
disorder  peculiarly  frequent  in  that  class  of  persons;  and  to 
indicate  that  fact  some  physicians  apply  the  term  "  drink- 
stroke"  to  that  disease. 


55.  How  does  alcohol  make  one  fleshy  ? 

56.  What  results  ?    What  change  in  the  blood  due  to  alcohol  ? 

57.  How  is  exhaustion  due  to  alcohol  ? 

08.  What  other  disorders  may  be  due  to  alcohol? 


THE  GIRCULATION  181 

59.  Action  of  Tobacco  on  the  Heart.  —  Tobacco  both  quickens 
and  enfeebles  the  heart.  In  some  of  those  who  habitually  use 
it,  it  gives  rise  to  a  throbbing  or  heaving  sensation  in  the 
region  of  the  heart,  an  exaggerated  kind  of  palpitation ;  at 
times,  this  is  so  tumultuous  that  the  patient  fears  lest  his  last 
hour  has  come.  In  other  cases,  there  is  a  weak  and  irregular 
heart-beat,  caused  by  tobacco  poisoning.  This  is  not  so  alarm- 
ing to  the  patient  as  the*. condition  just  mentioned,  but  is  no 
less  dangerous  and  much  less  easily  cured.  It  is  apt  to  injure 
a  man's  capacity  for  business  affairs,  being  repressive  of  health- 
ful energy  and  exertion. 

69.   What  two  noticeable  effects  from  tobaceo  ? 


182 


THE  CIRCULATION 


TOPICAL    OUTLINE 


HEART 


f  Right  Cavity 
I  Left  Cavity 

Right  Auricle 


CAVITIES  OF 
THE  HEART 


Right  Ventricle  . 


Left  Auricle 


Left  Ventricle 


BLOOD- 
VESSELS 


Arteries 


Capillaries 


Veins  . 


Right  auricle     j  Between    these    the   tri- 
Right  ventricle  )      cuspid  valve. 
Left  auricle       )  Between  these  the  bicus- 
Left  ventricle    \     pid  or  mitral  valve. 
Thin  irregular  walls. 

f  Vena  cava  superior — from  upper 

parts. 

Vena  cava  inferior  —  from  lower 
.  parts. 

Coronary  vein  —  which  returns 
the  venous    blood    from    the 
[      heart  walls. 
Thick  walls. 
Papillary  muscles. 
Chords^  tendineae. 
Three  cusps  —  form  the  tricuspid  valve. 


Vessels 


Vessels 


Right  pulmonary 
artery— to  right     Semilunar 
lung.  valves  just 

Left    pulmonary  j    belowjunc- 

artery  —  to  left  |     tion. 
.     lung. 
[  Thin  irregular  walls. 

r  Right   pulmonary    vein  —  from 

Vessels      r  ri"ht  Iun9- 

Left  pulmonary  vein  —  from  left 

{      lung. 
(  Very  thick  walls. 
Papillary  muscles. 
Chordse  tendinese. 
Two  cusps  —  form  the  bicuspid  or  mitral 

valve. 

Vessel  — The  aorta—  to  all  parts. 
Semilunar  valves  at  its  origin. 
Coronary  arteries  com-  ]  Supply  wails  of 
mence  just  outside  the  }•     heart        with 
semilunar  valves.          J      blood. 
Take  blood  from  the  heart. 
f  1.   Outer  areolar. 

2.  Middle  muscular  and  elastic 
Coats'   }      -thick. 

[  3.   Inner  epithelial. 

Assist  in  propelling  blood  by  their  elastic 
(      recoil. 

f  Connect  small  arteries  with  small  veins. 
j.  Arranged  like  networks. 
1  Very  thin  walls. 
(  Diameter  about  scVo  inch. 
(-  Convey  blood  to  the  heart. 
|  Coats  —  same  as  in  arteries,  but  less  mus- 
^      cular  and  elastic  tissue, 
j  Generally  provided  with  valves  —  like  the 
semilunars. 


THE  CIRCULATION 


183 


ACTION  OF 
THE  HEART 


Auricular 
Contraction 


Ventricular- 
Contraction 


Beating 


Sounds     .    . 


Simultaneous. 

Blood  forced  into  ventricles. 

Force  not  sufficient  to  cause  regurgitation 

into  the  veins. 
/•  Valves  between  the  auricles  and  ventricles 

closed . 

Chordae  tendineas  tightly  stretched. 
Semilunars  forced  open. 
Blood  forced  into  the  great  arteries. 
Apex  of  heart  tilted  forward  against  the 

front  wall  of  the  chest. 
From  (X)  (old  age)  to  120  (young  child )  per 

minute. 
\  Dull  sound — closure  of  tricuxpid  and  mitral 

valves,  and  contraction  of  ventricles  (?). 
Sharp  sound  —  sudden  closure  of  semilu- 

nars. 
Followed  by  a  pause. 


CIRCULATION 


COURSE  OF 
THE  BLOOD 


In  Arteries 


In  Capillaries 


In  Veins 


Causes 


In  jerks  (pulsations) 

Very  rapid. 

Elastic  recoil  tends  to  produce  a  continuous 

stream  in  the  smaller  arteries. 
f  Very  slow  and  uniform. 
\  Great  resistance  offered  by  the  capillary 
I     walls. 

{Much  faster  than  in  capillaries. 
Not  so  rapid  as  in  arteries. 
Steady  flow. 
Valves  prevent  backward  flow. 
(  Heart. 

i  Muscular  action. 
I  Respiration. 


Right  auricle. 
Right  ventricle. 
Pulmonary  arteries 
Lungs  (capillary  system). 
Pulmonary  veins. 
Left  auricle. 
Left  ventricle. 
Aorta. 

j  Capillary  networks  in  all  parts. 
Venae  cava3. 
Right  auricle. 
Capillaries    of    spleen,    pancreas, 

stomach,  intestines. 
Portal  vein. 
Capillaries  of  liver. 
Hepatic  vein. 
Inferior  vena  cava. 
Right  auricle. 


Pulmonary  Circulation. 


\  Systemic  Circulation. 


Portal  Circulation. 


184 


THE  CIRCULATION 


COMPOSITION 
OF  THE 
BLOOD 


CLOTTED 
BLOOD 


BLOOD 


LYMPH 


f  Plasma  . 


f  The  liquid  of  the  blood. 
Water. 


Corpuscles 


Serum    . 

Fibrin     . 
Corpuscles 

f  Arterial  . 


•J  Venous  .    . 


Temperature 
[  Quantity     . 

Source    .    . 
Uses  .    .    . 

Apparatus  . 

Causes  of 
(  Circulation 


I  White 


The  elements  of  fibrin. 

Discs,    round,   with    concave 

sides. 

Diameter,  351o5  inch. 
Thickness,  ujgjj  inch. 
Yellowish,  when  viewed  singly. 
Have  a  tendency  to  adhere  and 
form  piles  when  the  blood  is 
drawn. 

Hemoglobin,  the  oxygen  car- 
rier. 

(  Shape  constantly  varying. 
|  Diameter,  Woo  inch. 
j  Transparent,  jelly-like. 
(  One'  to  every  300  red. 


(  Water. 

j  Dissolved  mineral  salts. 

I  Dissolved  albumen. 

Formed  during  •) 
coagulation .    I  Clot — floats  in  the  serum . 

Red  and  white.  J 

Bright  red. 

Red  in  oxygen. 

Usually  contained  in  arteries. 

Dark  purple. 

Usually  found  in  veins. 

Contains  j  Lessox.Ygen  than  arterial  blood. 

(  More  carbonic  acid  gas. 
Converted  into  arterial  blood  by  absorp- 
tion of  oxygen. 
99°  F. 
One-tenth  the  weight  of  the  body. 

Plasma  of  blood  by  osmosis, 
j  Nourish. 
I  Excrete. 

{Lymphatic  capillaries. 
Lymphatic  ducts. 
Thoracic  duct. 
Lymphatic  glands. 
(  Muscular  action. 
(  Eespi  ration. 


THE  CIRCULATION  185 

TABLE  OF  THE   PRINCIPAL  ARTERIES 
(SEE  PLATE  OPPOSITE  PAGE  146) 


The  Head 


Oph-thal'n  c,  supplies  the  eye«* 

External  Ca-rot'id  f  Lin'gual»  supplies  the  tongue. 

if  \  Fa'"'*1'  supplies  the  lower  part  of  the  face. 

'  I  Tem'po-ral,  supplies  the  upper  part  of  the  head  and  face. 

The  Trunk 

The  A-or'ta,  arising  from  the  heart,  is  the  main  arterial  trunk. 

Cor'o-na-ry,  supplies  the  walls  of  the  heart. 

Bron'chi-al,  supplies  the  lungs. 

In-ter-cos'tals,  supply  the  walls  of  the  chest. 

Gas'tric,  supplies  the  stomach. 

He-pat'ic,  supplies  the  liver. 

Splen'ic,  supplies  the  spleen. 

Re'nal,  supplies  the  kidney. 

Mes-en-ter'ics,  supply  the  bowels. 

Spi'nal,  supplies  the  spinal  cord. 

The  Upper  Limb 

Branches  of  the  Ax-il-la'ry,  supply  the  shoulder. 
"  "       Bra'chi-al,  supply  the  arm. 

44  '„         *    *~    '  j  supply  the  forearm  and  fingers. 


The  Lower  Limb 

Branches  of  the  Fem'o-ral,  supply  the  hip  and  thigh. 
"  "       Pop-li-te'al, ) 

"       Tib'i-al,        Uupply  the  leg  and  foot. 
"  "       Per-o-ne'al,  J 


QUESTIONS    FOR    TOPICAL    REVIEW 

PAGE 

1.  In  what  organisms  is  the  so-called  circulatory  fluid  found  ? 152 

2.  How  is  it  designated  in  the  different  organisms  ? 152 

3.  What  can  you  state  of  the  importance  of  blood  to  the  body  ? 152 

4.  Of  its  great  abundance,  color,  and  composition  ? 152,  153 

5.  Describe  the  corpuscles  of  the  human  blood 153,  154 

(>.  What  is  said  of  them  in  comparison  with  those  of  the  lower,  animals?      153 

7.  Of  the  importance  of  sometimes  detecting  human  from  other  blood?      153 

8.  What  means  have  we  of  detecting  blood  in  spots  or  stains  ? 153 

9.  What  is  meant  by  coagulation  of  the  blood  ? 155 


186  THE  CIRCULATION 


PAGK 

10.  What  wisdom  is  there  in  the  law  of  the  blood's  coagulation  ? 155,  156 

11.  How  is  this  wisdom  made  manifest  ? 156 

12.  In  what  cases  is  the  aid  of  the  surgeon  required  ? 156 

13.  What  are  the  two  great  uses  of  the  blood  ? 156,  157 

14.  Through  what  mediums  is  the  blood  provided  with  new  material  and 

relieved  of  the  old  material? 157 

15.  What  do  you  understand  by  the  operation  called  transfusion  ? 157 

16.  What  cases  of  transfusion  are  reported  of  the  lower  animals  ? 158 

17.  What  can  you  state  of  transfusion  as  practised  upon  man  ? 157,  158 

18.  What  further  can  you  say  on  the  subject  ?  158 

19.  What  changes  take  place  in  the  color  of  the  blood  in  its  journey 

through  the  system  ? 158 

20.  State  all  you  can  in  relation  to  the  circulation  of  the  blood 159 

21.  All,  in  relation  to  the  size,  shape,  and  location  of  the  heart 160,  161 

22.  How  is  the  loss  of  power  in  the  heart-movements  obviated  ? 161 

23.  Give  a  description  of  the  formation  of  the  heart 161 

24.  What  can  you  state  of  the  ventricles  and  auricles  of  the  heart  ? 161 

25.  Describe  the  action  of  the  heart.' 162 

26.  What  special  vitality  does  the  tissue  of  the  heart  possess  ?. . . 163 

27.  State  all  you  can  on  the  subject 163 

28.  Describe  the  course  of  the  blood  through  the  cavities  of  the  heart.  163,  164 

29.  Describe  the  mechanism  that  regulates  the  heart-currents 164 

30.  How  do  you  account  for  the  two  heart-sounds  at  the  front  of  the 

chest  ? 164 

31.  State  what  you  can  of  the  frequency  of  the  heart's  action 164,  165 

32.  Of  the  activity  of  the  heart 166,  167 

33.  What  do  you  understand  by  the  arteries  ? 167,  168 

34.  State  what  you  can  of  the  arteries  and  the  arterial  system 168 

35.  What  do  you  understand  by  the  pulse  ? 169,  170 

36.  In  what  part  of  the  body  may  the  pulse  be  felt? 169 

37.  What  further  can  you  state  of  the  pulse  ? 169 

38.  What  are  the  veins? 170 

39.  Where  do  they  exist,  and  how  are  they  formed  ? 170 

40.  Describe  the  valves  of  the  veins  and  their  uses 171,  172 

41.  Now  give  a  full  description  of  the  construction  of  the  veins 171,  172 

42.  What  further  can  you  state  of  the  veins  ? 172 

43.  What  do  you  understand  by  the  capillaries  ? 172 

44.  What  service  do  the  capillaries  perform  ? 173,  174 

45.  What  can  you  state  of  the  rapidity  of  the  blood's  circulation  ?  ...  175,  176 

46.  Of  the  process  known  as  assimilation  ? 177 

47.  Of  injuries  to  the  blood-vessels  ? 178 

48.  What  is  the  effect  of  alcohol  upon  the  heart  ? 179,  180 

49.  What  is  said  of  alcohol  as  a  fat-producer  ? 180 


CHAPTER  VIII 

RESPIRATION 


< 


The  Objects  of  Respiration — The  Lungs  —  The  Air-passages — The 
Movements  of  Respiration  —  Expiration  and  Inspiration — The  Fre- 
quency of  Respiration —  Capacity  of  the  Lungs —  The  Air  we  Breathe 
—  Changes  in  the  Air  from  Respiration — Changes  in  the  Blood  — 
Interchange  of  Gases  in  the  Lungs —  Comparison  between  Arterial 
and  Venous  Blood  —  Respiratory  Labor  —  Impurities  of  the  Air  — 
Dust — Carbonic  Acid  —  Effects  of  Impure  Air  —  Nature's  Provision 
for  Purifying  the  Air — Ventilation — Animal  Heat  —  /Spontaneous 
Combustion 

1.  The  Object  of  Respiration. — In  one  set  of  capillaries,  or 
hair-like  vessels,  the  blood  is  impoverished  in  order  to  support 
the  different  members  and  organs  of  the  body.     In  another 
capillary  system  the  blood  is  refreshed  and  again  made  fit  to 
sustain  life.     The  former  belongs  to  the  greater  or  systemic  cir- 
culation ;  the  latter  to  the  lesser  or  pulmonary,  so  called  from 
pulmo,  the  lungs,  in  which  organs  it  is  situated.     The  blood,  as 
sent  from  the  right  side  of  the  heart  to  the  lungs,  is  venous, 
dark,  impure,  and  of  a  nature  hurtful  to  the  tissues.     But, 
when  the  blood  returns  from  the  lungs  to  the  left  side  of  the 
heart,  it  has  become  arterial,  bright,  pure,  and  no  longer  injuri- 
ous.    This  marvellous  purifying  change  is  effected  by  means 
of  the  very  familiar-  act  of  respiration,  or  breathing. 

2.  The  Lungs. — The  lungs  are  the  special  organs  of  respi- 
ration.    Theie  are  two  of  them,  one  on  each  side  of  the  chest, 
which  cavity  they,  with  the  heart,  almost  wholly  fill.     The 
lung-substance  is  soft,  elastic,  and  sponge-like.     Under  pres- 
sure of  the  finger,  it  crepitates,  or  crackles,  and  floats  when 

1.  Difference  between  the  two  sets  of  capillaries  ?    Change  effected  by  respiration  or 
breathing  ? 

2.  What  are  the  lungs  ?    How  many  lungS  are  there  ?    Lung-substance  ?    Its  proper- 
ties?  The  pleura? 

187 


188  RESPIRATION 

thrown  into  water ;  these  properties  being  due  to  the  presence 
of  air  in  the  minute  air-cells  of  the  lungs.  To  facilitate  the 
movements  necessary  to  these  organs,  each  of  them  is  provided 
with  a  double  covering  of  an  exceedingly  smooth  and  delicate 
membrane,  called  the  pleura.  One  layer  of  the  pleura  is 


T) 


FIG.  47.  —  ORGANS  OF  THE  CHEST 

A,  Lungs  D,  Pulmonary  Artery 

B,  Heart  E,  Trachea 

attached  to  the  walls  of  the  chest,  and  the  other  to  the  lungs ; 
and  they  glide,  one  upon  the  other,  with  utmost  freedom. 
Like  the  membrane  which  envelops  the  heart,  the  pleura 
secretes  its  own  lubricating  fluid,  in  quantities  sufficient  to 
keep  it  always  moist. 

3.  The  Air-Passages. — The  lungs  communicate  with  the 
external  air  by  means  of  certain  air-tubes,  the  longest  of 
which  —  the  trachea,  or  windpipe  —  runs  along  the  front  of 

3.   Communication  of  the  lungs  with  the  external  air  ?    Bronchial  tubes  ? 


RESPIRATION 


189 


the  neck  (Fig.  47,  E,  and  48).  Within  the  chest  this  tube  is 
divided  into  two  branches,  one  entering  each  lung;  these  in 
turn  give  rise  to  numerous  branches,  or  bronchial  tubes,  as 
they  are  called,  which  gradually  diminish  in  size  until  they 
are  about  one  twenty-fifth  of  an  inch  in  diameter.  Each  of 
these  terminates  in  a  cluster  of  little  pouches,  or  "  air-cells," 
having  very  thin  walls,  and  covered  with  a  capillary  network, 
the  most  intricate  in  the  body  (Fig.  49). 

4.   These  tubes  are  somewhat  flexible,  sufficiently  so  to  bend 
when  the  parts  in  which  they  are  situated  move  j  but  they  are 


FIG.  48. — LARYNX,  TRACHEA,  AND 
BRONCHIAL  TUBES 


FIG.  49.  —DIAGRAM  AND  SECTION  OF 
THE  AIR-CELLS 


greatly  strengthened  by  bands  or  rings  of  cartilage  which  keep 
the  passages  always  open;  otherwise  there  would  be  a  con- 
stantly-recurring tendency  to  collapse  after  every  breath.  The 
lung-substance  essentially  consists  of  these  bronchial  tubes 
and  terminal  air-cells,  with  the  blood-vessels  ramifying  about 
them  (Fig.  50).  At  the  top  of  the  trachea  is  the  larynx,  a 
sort  of  box  of  cartilage,  across  which  are  stretched  the  vocal 


4.  Office  of  the  bronchial  tubes  ?    What  further  can  you  state  of  th«iu  1 


190 


EESPIRATION 


cords.     Here  the  voice  is  produced  chiefly  by  the  passage  of  the 
respired  air  over  these  cords,  causing  them  to  vibrate  (Fig.  51) 

5.  Over  the  opening  of  the  larynx  is  found  the  epiglottis, 
which  fits  like  the  lid  of  a  box  at  the  entrance  to  the  lungs, 
and  closes  during  the  act  of  swallowing,  so  that  food  and 
drink  shall  pass  backward  to  the  oesophagus,  or  gullet  (Fig. 
51).  Occasionally  it  does  not  close  in  time,  and  some  sub- 
stance intrudes  within  the  larynx,  when  we  at  once  discover, 
by  a  choking  sensation,  that  "  something  has  gone  the  wrong 


FIG.  50.  —  SECTION  OF  THE  LUNGS 


way,"  and,  by  coughing,  we  attempt  to  expel  the  unwelcome 
intruder.  The  epiglottis  is  one  of  the  many  safeguards  fur- 
nished by  nature  for  our  security  and  comfort,  and  is  planned 
and  put  in  place  long  before  these  organs  are  brought  into 
actual  use  in  breathing  and  in  taking  food. 

6.   The  air-passages  are  lined  throughout  almost  their  whole 
extent  with  mucous  membrane,  which  keeps  them  in  a  con- 

5.  The  epiglottis  ?    When  it  does  not  close  in  time,  what  is  the  consequence  ? 

6.  Lining  of  the  air-passages  ?    Ciliated  cells  ?    Their  uses  ?    The  three  diseases  of  the 
lungs  ? 


RESPIRATION 


191 


stantly  moict  condition.  This  membrane  has  cells  of  a 
peculiar  kind  upon  its  outer  surface.  If  examined  under  a 
powerful  microscope,  we  may  see,  even  for  a  considerable  time 
after  their  removal  from  the  body,  that  these  cells  have  minute 
hair-like  processes  in  motion,  which  wave  like  a  field  of  grain 


Flo.  51.  —  SECTION  OF  THE  MOUTII  AND  THROAT 


A,  The  Tongue 

B,  The  Uvula 


C,  Vocal  Cord 
E,  Epiglottis 
L,  Larynx 


N,  Trachea 
O,  lEsophagus 


under  the  influence  of  a  breeze  (Fig.  52).  This  is  a  truly 
beautiful  sight ;  and  since  it  is  found  that  these  little  cilia,  as 
they  are  called,  always  produca  currents  in  one  direction  — 
from  within  outward — it  is  probable  that  they  serve  a  useful 
purpose  in  catching  and  carrying  away  from  the  lungs  dust 


192  RESPIRATION 

and  other  small  particles  drawn  in  with  the  breath  (Fig.  52). 
The  three  diseases  which  more  commonly  affect  the  lungs,  as 
the  result  of  exposure,  are  pneumonia,  or  inflammation  of  the 
lungs,  affecting,  principally,  the  air-cells ;  bronchitis,  an  inflam- 
mation of  the  large  bronchial  tubes ;  and  pleurisy,  an  inflamma- 
tion of  the  pleura,  or  outside  wrapping  of  the  lungs.  Among 
the  young,  an  inflammation  of  the  trachea  takes  place,  known 
as  croup. 

7.  The  Movements  of  Respiration.  —  The  act  of  breathing  has 
two  parts  —  (1),  inspiration,  or  drawing  air  into  the  lungs,  and 
(2),  expiration,  or  driving  it  out  again.     In  inspiration,  the 

chest  extends  in  its  length,  breadth, 
and  height.  The  motion  outward  and 
upward  can  be  observed  every  time 
we  draw  a  full  breath ;  and  is  caused 
by  a  lifting  .of  the  ribs.  But  the  mo- 
tion downward  is  not  so  apparent,  as 
it  is  caused  by  a  muscle  within  the 
PIG.  52.— CILIATED  CELLS  HIGHLY  body  called  the  diaphragm.  This  is 

MAGNIFIED  ,  .  .     .  . 

the  thin  partition  which  separates  the 

chest  from  the-  abdomen,  rising  like  a  dome  within  the  chest 
(Fig.  22). 

8.  With  every  inspiration  the  diaphragm  contracts,  and  in 
so  doing,  approaches  more  nearly  a  level  surface,  and  thus 
enlarges  the  capacity  of  the  chest.     Laughing,  sobbing,  and 
sneezing  are  due  to  sudden  action  of  the  diaphragm.     On  the 
proper  acting  of  this  muscle  depends  our  power  to  breathe 
deeply;   and  like  other  muscles,  its  strength  is  increased  by 
exercise.     This  gives  that  endurance,  or  "  long  wind,"  as  it  is 
commonly  called,  which  is  possessed  in  a  marked  degree  by 
the  mountaineer,  the  oarsman,  and  the  trained  singer.     The 
habit  of  taking  frequent  and  deep  inspirations,  in  the  erect 
position,  with  the   shoulders  thrown  back,   tends    greatly  to 
increase  the  capacity  and  power  of  the  organs  of  respiration. 

7.  The  act  of  breathing  ?    Extension  of  the  chest  by  breathing  ? 

8.  Contraction  of  the  diaphragm  ?    Power  of  the  diaphragm  ?    Effects  of  extending  the 
walls  of  the  chest  ?    The  habit  of  taking  frequent  and  deep  inspirations  ? 


RESPIRATION  193 

9.  Expiration  is  a  less  powerful  act  than  inspiration.     The 
diaphragm  relaxes,  and  ascends  in  the  form  of  a  dome;  the 
ribs  descend  and  contract  the  chest;   while  the  lungs  them- 
selves, being  elastic,  assist  to  drive  out  the  air.     The  latter 
passes  out  through  the  same  channels  by  which  it  entered. 
At  the  end  of  each  expiration  there  is  a  period  of  repose,  last- 
ing about  as  long  as  the  period  of  action. 

10.  Frequency  of  Respiration.  — It  is  usually  estimated  that 
we  breathe  once  during  every  four  beats  of  the  heart,  or  about 
eighteen  times  in  a  minute.     There  is,  of  course,  a  close  rela- 
tion between  the  heart  and  lungs,  and  whatever  modifies  the 
pulse,  in  like  manner  affects  the  breathing.     When  the  action 
of  the  heart  is  hurried,  a  larger  amount  of  blood  is  sent  to  the 
lungs,  and,  as  a  consequence,  they  must  act  more  rapidly. 
Occasionally,  the  heart  beats  so  very  forcibly  that  the  lungs 
cannot  keep  pace  with  it,  and  then  we  experience  a  peculiar 
sense  of  distress  from  the  want  of  air.     This  takes  place  when 
we  run  until  we  are  "out  of  breath."    At  the  end  of  every 
fifth  or  sixth  breath,  the  inspiration  is  generally  longer  than 
usual,  the  effect  being  to  change  more  completely  the  air  of 
the  lungs.     (Head  Note  1.) 

1.  Experiment.  The  Lungs  —  Respiration.  —  Obtain  from  your 
butcher  a  pair  of  sheep's  or  calf's  lungs ;  they  should  be  cut  out  with 
great  care,  so  as  not  to  be  injured  in  any  part.  Insert  the  nozzle  of  a 
pair  of  bellows  into  the  trachea  and  tie  it  securely  ;  then  inflate  the  lungs 
fully,  and  tie  the  trachea  just  below  the  point  of  the  nozzle  very  securely, 
so  that  no  air  escapes.  Now  hang  the  lungs  up  to  dry.  If  there  is  no 
hole  in  any  part  of  them,  they  will  retain  the  air  sufficiently  long  to  allow 
the  air-cells  to  dry  in  this  distended  state.  During  the  drying  the  lungs 
will  shrink  somewhat,  but  that  will  not  interfere  with  the  demonstration 
of  the  specimen.  When  thoroughly  dry,  cut  through  both  lungs  length- 
wise (see  Fig.  50,  page  180)  with  a  long,  sharp  knife.  You  will  then  obtain 
a  very  interesting  and  valuable  specimen,  which  will  keep  for  a  long  time 
if  protected  from  dust.  It  shows  the  trachea  and  its  structure,  bronchi 
and  their  subdivision,'  and  the  terminal  air-cells. 

The  presence  of  carbonic  acid  gas  in  the  expired  air  may  be  demon- 
strated by  blowing  air  through  some  perfectly  clear  lime  water,  by  means 
of  a  glass  tube.  Carbonic  acid  gas  produces  a  chemical  change  in  the 
lime  contained  in  the  water,  transforming  it  into  carbonate  of  lime,  which 

9.  Expiration  ?    The  mechanism  of  expiration  ? 
10.  Frequency  of  respiration  ?    Effect  of  hurried  action  of  the  heart? 


194  RESPIRATION 

11.  Although,  as  a  general  rule,  the  work  of  respiration  goes 
on  unconsciously  and  without  exertion  on  our  part,  it  is,  never- 
theless, under  the  control  of  the  will.  We  can  increase  or 
diminish  the  frequency  of  its  acts  at  pleasure,  and  we  can 
"hold  the  breath,"  or  arrest  it  altogether  for  a  short  time. 
From  twenty  to  thirty  seconds  is  ordinarily  the  longest  period 
in  which  the  breath  can  be  held;,  but  if  we  first  expel  all  the 
impure  air  from  the  lungs,  by  taking  several  very  deep  inspira- 
tions,, the  time  may  be  extended  to  one  and  a  half  or  even  two 
minutes.  This  should  be  remembered,  and  acted  upon,  before 
passing  through  a  burning  building,  or  any  place  where  the  air 
is,  ye-ry  foul.  The  arrest  of  the  respiration  may  be  still  further 
prolonged  by  training  and  habit.  It  is  said  that  the  pearl- 
fishers  of  India  can  remain  three  o*  four  minutes  under  water 
without  being  compelled  to  breathe. 

18.  Capacity  of  the  Lungs. — The  lungs  ape  not  filled  and 
emptied  by  each  respiration.  For  while  their  full  capacity,  in 
the  adult,  is  three  hundred  and  twenty  cubic  inches,  or  more 
than  a  gallon,  the  ordinary  breathing  air  is  only  one-sixteenth 
part  of  that  volume,  or  twenty  cubic  inches  —  being  two-thirds 
of  a  pint.  Accordingly,  a  complete  renovation,  or  rotation,  of 
the  air  of  the  lungs  does  not  take  place  more  frequently  than 
about  once  a  minute ;  and  by  the  gradual  introduction  of  the 
external  air,  its  temperature  is  considerably  elevated  before  it 
reaches  the  delicate  capillaries  that  surround  the  air-cells.  In 
tranquil  respiration,  less  than  two-thirds  of  the  breathing  power 
is.  called  into  exercise,  leaving  a  reserve  capacity  of  about  one 
hundred  and  twenty  cubic  inches,  equivalent  to  three  and  one- 
half  pints.  This  provision  is  indispensable  to  the  continua- 
tion of  life;  otherwise,  a  slight  interference  with  respiration 
—  by  an  ordinary  cold,  for  instance — would  suffice  to  cut 

is  insoluble  in  water.  After  the  air  has  been  blown  through  for  a  few 
minutes,  the  water  becomes  turbid,  and  after  a  longer  time,  milky.  Upon 
standing,  this  milkiness  subsides  to  the  bottom  in  the  form  of  a  fine  pow- 
der, carbonate  of  lime. 

11.  Kespira'tion  controlled  by  the  will  ?    Advantage  of  the  knowledge  to  us  ? 

12.  Capacity  of  the  lungs?    Time  required  to  renovate  the  air  in  the  lungs?    In  tran- 
quil respiration  ?    Importance  of  the  provision  ? 


RESPIRATION  195 

off  the  necessary  air,  and  the  spark  of  life  would  be  speedily 
extinguished. 

13.  The  Air  we  Breathe.  —  The  earth  is  enveloped  on  all 
sides  by  an  invisible  fluid,  called  the  atmosphere.     It  forms  a 
vast  ocean  of  air,  forty-five  miles  deep,  encircling  and  per- 
vading all  objects  on  the  earth's  surface,  and  is  absolutely 
essential  for  the  preservation  of  all  vegetable  and  animal  life 
—  in  the  sea,  as  well  asxon  the  land  and  in  the  air.     At  the 
bottom,  or  in  the  lower  strata  of  this  ocean  of  air,  we  move 
and  have  our  being.     Perfectly  pure  water  will  not  support 
marine  life,  for  a  fish  may  be  drowned  in  water  from  which 
the  air  has  been  exhausted,  just  as  certainly  as  a  mouse,  or 
any  other  land  animal  will  perish  if  held  under  water  for  a 
short  time.     The  cause  is  the  same  in  both  cases  —  the  animal 
is  deprived  of  the  requisite  amount  of  air.     It  is  also  stated, 
that  if  the  water-supply  of  the  plant  be  deprived  of  air,  its 
growth  is  checked.     (Read  Note  2.) 

14.  The  air  is  not  a  simple  element,  as  the  ancients  sup- 
posed, but  is  formed  by  the  mingling  of  two  gases,  known  to 

2.  The  Atmosphere.  —  "  It  surrounds  us  on  all  sides,  yet  we  see  it  not ; 
it  presses  on  us  with  a  load  of  fifteen  pounds  to  every  square  inch  of  sur- 
face of  our  bodies,  or  from  seventy  to  one  hundred  tons  on  us  in  all,  yet 
we  do  not  so  much  as  feel  its  weight.  Softer  than  the  softest  down  — 
more  impalpable  than  the  finest  gossamer  —  it  leaves  the  cobweb  undis- 
turbed, and  scarcely  stirs  the  lightest  flower  that  feeds  on  the  dew  it  sup- 
plies ;  yet  it  bears  the  fleets  of  nations  on  its  wings  around  the  world, 
and  crushes  the  most  refractory  substances  beneath  its  weight.  When  in 
motion,  its  force  is  sufficient  to  level  the  most  stately  forests  with  the 
earth ;  to  raise  the  waters  of  the  ocean  into  ridges  like  mountains,  and 
dash  the  strongest  ships  to  pieces  like  toys.  It  bends  the  rays  of  the  sun 
from  their  path,  to  give  us  the  twilight  of  evening  and  of  dawn ;  it  dis- 
perses and  refracts  their  various  tints,  to  beautify  the  approach  and 
retreat  of  the  orb  of  day.  But  for  the  atmosphere,  sunshine  would  burst 
on  us  and  fail  us  at  once,  and  at  once  remove  us  from  midnight  darkness 
to  the  blaze  of  noon.  We  should  have  no  twilght  to  soften  and  beautify 
the  landscape,  no  clouds  to  shade  us  from  the  scorching  heat ;  but  the 
bald  earth,  as  it  revolved  on  its  axis,  would  turn  its  tanned  and  weakened 
front  to  the  full  and  unmitigated  rays  of  the  lord  of  day."  — Buish. 


13.  The  atmosphere  ?    How  high  or  deep  ?    How  essential  to  life  ?    Marine  life  in  per- 
fectly pure  water  and  air  ? 

14.  Composition  of  the  air  1    Properties  of  the  two  gases  ? 


196  RESPIRATION 

the  chemist  as  oxygen  and  nitrogen,  in  the  proportion  of  one 
part  of  the  former  to  four  parts  of  the  latter.  These  gases  are 
very  unlike,  being  almost  opposite  in  their  properties  :  nitrogen 
is  weak,  inert,  and  cannot  support  life :  while  oxygen  is  power- 
ful, and  incessantly  active,  and  is  the  essential  element  which 
gives  to  the  atmosphere  its  power  to  support  life  and  com- 
bustion. The  discovery  of  this  fact  was  made  by  the  French 
chemist,  Lavoisier,  in  1778. 

15.  Changes  in  the  Air  from  Respiration.  —  Air  that  has  been 
once  breathed  is  no  longer  fit  for  respiration.     An  animal  con- 
fined within  it  will  soon  die ;  so,  also,  a  lighted  candle  placed 
in  it  will  be  at  once  extinguished.     If  we  collect  a  quantity  of 
expired  air  and  analyze  it,  we  shall  find  that  its  composition 
is  not  the  same  as  that  of  the  inspired  air.     When  the  air 
entered  the   lungs   it  was   rich  in  oxygen ;    now  it  contains 
twenty-five  per  cent,  less  of  that  gas.     Its  volume,  however, 
remains  nearly  the  same  —  its  loss  being  made  up  by  another 
and  very  different  gas,  which  the  lungs  exhale,  called  carbonic 
acid  gas,  or,  as  the  chemist  terms  it,  carbon  dioxide. 

16.  The  expired  air  has  also  gained  moisture.     This  is  no- 
ticed when  we  breathe  upon  a  mirror  or  the  windowTpane,  the 
surface  being  tarnished  by  the  condensation  of  the  watery  vapor 
given  off  by  the  lungs.     In  cold  weather,  this  causes  the  fine 
cloud  which  is  seen  issuing  from  the  nostrils  or  mouth  with  each 
expiration,  and  contributes  in  forming  the  feathery  crystals  of 
ice  which  decorate  our  window-panes  on  a  winter's  morning. 

17.  This  watery  vapor  contains  a  variable  quantity  of  ani- 
mal matter,  the  exact  nature  of  which  is  unknown ;  but  when 
collected  it  speedily  putrefies  and  becomes  highly  offensive. 
From  the  effects,  upon  small  animals,  of  confinement  in  their 
own  exhalations,  having  at  the  same  time  an  abundant  supply 
of  fresh  air,  it  is  believed  that  the  organic  matters  thrown  off 
by  the  lungs  and  skin  are  direct  and  active  poisons ;  and  that 

15.  Air  once  breathed  ?    An  animal  in    it  ?    A    candle  ?    Analysis    of  expired   air  ? 
Change  in  volume  ? 

16.  What  else  has  the  expired  air  gained  ?    When  and  where  noticed  ? 

17.  Nature  of  the  watery  vapor  ?    Its  effects  upon  animals  ? 


RESPIRATION  197 

to  such  emanations  from  the  body,  more  than  to  any  other 
cause,  are  due  the  depressing  and  even  fatal  results  which 
follow  the  crowding  of  large  numbers  of  persons  into  places 
of  limited  capacity.  (Read  Note  3.) 

18.  History  furnishes  many  painful  instances  of  the  ill 
effects  of  overcrowding.  In  1756,  of  one  hundred  and  forty- 
six  Englishmen  imprisoned  in  the  Black  Hole  of  Calcutta, 
only  twenty-three,  at  the  elid  of  eight  hours,  survived.  After 
the  battle  of  Austerlitz,  three  hundred  prisoners  were  crowded 
into  a  cavern,  where,  in  a  few  hours,  two-thirds  of  their  num- 

3.  The  Two  Breaths.  —  "  Every  time  you  breathe,  you  breathe  two 
different  breaths :  you  take  in  one,  you  give  out  another.  The  compo- 
sition of  those  two  breaths  is  different.  Their  effects  are  different.  The 
breath  which  has  been  breathed  out  must  not  be  breathed  in  again.  To 
tell  you  why  it  must  not  would  lead  me  into  anatomical  details,  not  quite 
in  place  here  as  yet ;  but  this  I  may  say :  those  who  habitually  take  in 
fresh  breath  will  probably  grow  up  large,  strong,  ruddy,  cheerful,  active, 
clear-headed  —  fit  for  their  work.  Those  who  habitually  take  in  the 
breath  which  has  been  breathed  out  by  themselves,  or  any  other  living 
creature,  will  certainly  grow  up  —  if  they  grow  up  at  all  —  small,  weak, 
pale,  nervous,  depressed,  unfit  for  work,  and  tempted  continually  to 
resort  to  stimulants  and  become  drunkards. 

"  If  you  want  to  see  how  different  the  breath  breathed  out  is  from  the 
breath  taken  in,  you  have  only  to  try  a  somewhat  cruel  experiment,  but 
one  which  people  too  often  try  upon  themselves,  their  children,  and  their 
work-people.  If  you  take  any  small  animal  with  lungs  like  your  own  — 
a  mouse  for  instance  —  and  force  it  to  breathe  no  air  but  what  you  have 
breathed  already ;  if  you  put  it  in  a  close  box,  and,  while  you  take  in 
breath  from  the  outer  air,  send  out  your  breath  through  a  tube  into  that 
box,  the  animal  will  soon  faint ;  if  you  go  on  long  with  this  process,  he 
will  die.  *  *  *  *  What  becomes  of  this  breath  which  passes  from 
your  lips  ?  Is  it  merely  harmful,  merely  waste  ?  God  forbid  !  God  has 
forbidden  that  anything  should  be  merely  harmful  or  merely  waste  in  this 
so  wise  and  well-made  world.  The  carbonic  acid  gas  which  passes  from 
your  lips  at  every  breath  is  a  precious  boon  to  thousands  of  things  of 
which  you  have  daily  need.  For  though  you  must  not  breathe  your 
breath  again,  you  may  at  least  eat  your  breath,  if  you  will  allow  the  sun 
to  transmute  it  for  you  into  vegetables ;  or  you  may  enjoy  its  fragrance 
and  its  color  in  the  shape  of  a  lily  or  a  rose.  When  you  walk  in  a  sun- 
lit garden,  every  word  you  speak,  every  breath  you  breathe,  is  feeding 
the  plants  and  flowers  around." — Rev.  Charles  Kingsley  on  the  Two 
Breaths. 


18.  Give  some  of  the  instances  furnished  by  history. 


198  RESPIRATION 

her  died.  On  board  a  steamship,  during  a  stormy  night,  one 
hundred  and  fifty  passengers  were  confined  in  a  small  cabin, 
but  when  morning  came,  only  eighty  remained  alive. 

19.  Changes  in  the  Blood  from  Respiration.  —  The  most  strik- 
ing change  which  the  blood  undergoes  by  its  passage  through 
the  lungs,  is  the  change  of  color  from  a  dark  blue  to  a  bright 
red.     That  this  change  is  dependent  upon  respiration  has  been 
fully  proved  by  experiment.     If  the  trachea,  or  windpipe,  of  a 
living  animal  be  so  compressed  as  to  exclude  the  air  from  the 
lungs,  the  blood  in  the  arteries  will  gradually  grow  darker, 
until  its  color  is  the  same  as  that  of  the  venous  blood.     When 
the  pressure  is  removed,  the  blood  speedily  resumes  its  bright 
hue.     Again,  if  an  animal  breathes  an  atmosphere  containing 
more  oxygen  than  atmospheric  air,  the  color  changes  from 
scarlet  to  vermilion,  and  becomes  even  brighter  than  arterial 
blood.     This  change  of  color  is  not  of  itself  a  very  important 
matter,  but  it  indicates  a  most  important  change   of  com- 
position.    (See  Note  4.) 

20.  The  air,  as  we  have  seen,  by  respiration  loses  oxygen 
and  gains  carbonic  acid  gas;  the  blood,  on  the  contrary,  gains 
oxygen  and  loses  carbonic  acid  gas.     Oxygen  is  the  food  of  the 
blood  corpuscles ;  while  the  articles  we  eat  and  drink  go  more 
directly  to  the  plasma  of  the  blood.     The  air,  then,  it  is  plain, 

4.  Experiment.  Changes  in  the  Color  of  the  Blood.  —  The  changes 
produced  in  the  blood  by  the  atmosphere  are  of  easy  demonstration 
before  a  class.  Obtain  from  a  butcher  some  freshly  "whipped"  blood, 
i.e.,  blood  rapidly  stirred  with  a  bundle  of  twigs  while  it  is  being  drawn 
from  the  animal.  This  removes  all  the  fibrin,  and  the  blood  no  longer 
coagulates.  Upon  standing,  this  gradually  assumes  a  dark-brown  color. 

To  show  that  the  atmosphere,  or  rather  the  oxygen  in  the  atmosphere, 
produces  the  bright  red  or  arterial  blood,  fill  a  pint  bottle  of  white  glass 
about  one-third  full  with  this  dark  blood,  and  shake  it  briskly  ;  it  will 
very  promptly  assume  a  brighter  color.  The  same,  or  a  rather  better 
result  may  be  obtained  by  blowing  air  through  the  blood  by  means  of  a 
glass  tube  inserted  into  the  bottle  nearly  to  the  bottom.  After  having 
blown  air  through  for  a  few  minutes,  the  blood  assumes  a  bright  scarlet 
color.  Upon  standing  it  again  gradually  grows  dark. 


19.  Change  in  the  blood  from  blue  to  red.     Upon  what  does  the  change  depend  ?    How 
shown? 

20.  What  does  the  air  lose  and  gain  by  respiration  ?    What,  the  blood  ?    Air  as  food  ? 


RESPIRATION  199 

-*  \ 

is  a  sort  of  food,  and  we  should  undoubtedly  so  regard  it,  if  it 
were  not  for  the  fact  that  we  require  it  constantly,  instead  of 
taking  it  at  stated  intervals,  as  is  the  case  with  our  articles 
of  diet.  Again,  as  the  demand  of  the  system  for  food  is 
expressed  by  the  sensation  of  hunger,  so  the  demand  for  air  is 
marked  by  a  painful  sensation  called  suffocation. 

21.  Interchange  of  Gases  in  the  Lungs.  —  But  the  air  and  the 
blood  are  not  in  contact,  ^s  they  are  separated  from  each  other 
by  the  walls  of  the  air-cells  and  of  the  blood-vessels.     How 
then  do  the  two  gases,  oxygen  and  carbonic  acid  gas,  exchange 
places?     Moist  animal   membranes   have   a  property   which 
enables   them  to   transmit    gases    through    their    substance, 
although  they  are  impervious  to  liquids.     This  may  be  beau- 
tifully shown  by  suspending  a  bladder  containing  dark  venous 
blood  in  a  jar  of  oxygen.     At  the  end  of  a  few  hours  the 
oxygen  will  have  diminished,  the  blood  will  be  brighter  in 
color,  and  carbonic  acid  gas  will  Be  found  in  the  jar. 

22.  If  this  interchange  take  place  outside  of  the  body,  it 
must  take  place  more  perfectly  within  it,  where  it  is  favored 
by  many  additional  circumstances.     The  walls  of  the  vessels 
and  the  air-ceils  offer  no  obstacle  to  this  process,  which  is 
known  as  gaseous  diffusion.     Both  parts  of  this  process  of 
exchange  are  equally  important.     Without  oxygen  life  ceases ; 
if  carbonic  acid  gas  is  not  thrown  off,  it  acts  like  a  poison,  pro- 
ducing unconsciousness,  convulsions,  and  death. 

23.  Difference  between  Arterial  and  Venous  Blood.  —  The  fol- 
lowing table  presents  the  essential  points  of  difference  in  the 
appearance  and  composition  of  the  blood,  before  and  after  its 
passage  through  the  lungs : 

Venous  Blood.  Arterial  Blood. 

Color,  Dark  blue,  Scarlet. 

Oxygen,  8  per  cent. ,  18  per  cent. 

Carbonic  Acid  Gas,  15  to  20  per  cent.,  6  per  cent.,  or  less. 

Water,  More,  Less. 

The  temperature  of  the  blood  varies  considerably;  but  the 
arterial  stream  is  generally  warmer  than  the  venous.  The 

•Jl .    Moist  animal  membranes  ?    How  shown  with  the  bladder  ? 
22.   Gaseous  diffusion  ?    If  oxygen  be  not  received  ?    If  carbonic  acid  be  retained  ? 
28.  Difference  in  the  appearance  and  composition  of  the  blood  ?    Temperature  of  the 
blood  ?    The  blood  while  passing  through  the  lungs  ?    The  consequence  f 


200  RESPIRATION 

blood  imparts  heat  to  the  air  while  passing  through  the  lungs, 
and  consequently  the  contents  of  the  right  side  of  the  heart 
have  a  higher  temperature  than  the  contents  of  the  left  side.* 

24.  By  means  of  the  spectroscope,  we  learn  that  the  change 
of  color  in  the  blood  has  its  seat  in  the  corpuscles ;   and  that, 
according  as  they  retain  oxygen,  or  release  it,  they  present  the 
spectrum  of   arterial  or  of  venous  blood.      There   evidently 
exists,  on  the  part  of  these  little  bodies,  an  affinity  for  this  gas, 
and  hence  they  have  been  called  "  carriers  of  oxygen."    It  was 
long  ago  thought  that  blue  blood  was  peculiar  to  persons  of 
princely  or  royal  descent,  and  boastful  allusions  to  the  "  sang 
azure"  of  kings  and  nobles  are  often  met  with.     Physiology, 
however,  informs  us  that  blue  blood  flows  in  the  veins  of  all  — 
the  low  as  well  as  the  high — and  really  indicates  waste  and  decay. 

25.  Respiration  of  Cells.  —  The  blood  of  the  capillary  arteries 
coining  from  the  lungs,  where  it  has  been  supplied  with  oxygen, 
passes  through  the  tissues  of  all  parts  of  the  body  as  already 
stated,  and  here  each  cell  receives  its  necessary  supply  of  oxy- 
gen from  the  blood,  and  gives  up  in  return  carbon  dioxide  and 
other  waste  matters,  which  are  then  carried  through  the  veins 
to  the  organs  of  excretion. 

26.  Amount  of  Respiratory  Labor.  —  During  ordinary  calm 
respiration,  we  breathe  eighteen  times  in  a  minute ;  and  twenty 
cubic  inches  of  air  pass  in  and  out  of  the  lungs  with  every 
breath.     This  is  equivalent  to  the  use  of  three  hundred  and 
sixty  cubic  inches,  or  more  than  ten  pints  of  air  each  minute. 
From  this  we  calculate  that  the  quantity  of  air  which  hourly 
traverses  the  lungs  is  about  thirteen  cubic  feet,  or  seventy-eight 
gallons ;  and  daily,  not  less  than  three  hundred  cubic  feet,  or 
nearly  sixty  barrels. 

27.  Of  this  large  volume  of  air  five  per  cent,  is  absorbed  in 
its  transit  through  the  lungs.     The  loss  thus  sustained  is  almost 
wholly  of  oxygen,  and  amounts  to  fifteen  cubic  feet  daily.     The 
quantity  of  carbonic  acid  gas  exhaled  by  the  lungs  during  the 
day  is  somewhat  less,  being  twelve  cubic  feet.     Under  the  in- 

24.   What  do  we  learn  by  means  of  the  spectroscope  ?  25.   Respiration  of  cells  ? 

26.  Amount  of  air  that  passes  in  and  out  of  the  lungs  ? 

27.  Air  absorbed  in  its  transit  through  the  lungs  ? 


RESPIRATION  201 

fluence  of  excitement  or  exertion,  the  breathing  becomes  more 
frequent  and  more  profound ;  and  then  the  internal  respiratory 
work  increases  proportionately,  and  may  even  be  double  that 
of  the  above  estimate.  It  has  been  estimated  that  in  drawing 
a  full  breath,  a  man  exerts  a  muscular  force  equal  to  raising 
two  hundred  pounds  placed  upon  the  chest. 

28.  Impurities  of  the  Air. — The  oxygen  in  the  atmosphere 
is  of  such  prime  importance,  and  its  proportion  is  so  nicely 
adjusted  to  the  wants  of  man,  that  any  gas  or  volatile  substance 
which  supplants  it  must  be  regarded  as  a  hurtful  impurity. 
All  gases,  however,  are  not  alike  injurious.      Some,  if  inhaled, 
are  necessarily  fatal ;   arsenuretted  hydrogen  being  one  of  these, 
a  single  bubble  of  which  destroyed  the  life  of  its  discoverer, 
Gehlen.     Others  are  not  directly  dangerous,  but  because  they 
take  the  place  of  oxygen,  and  exclude  it  from  the  lungs,  they 
do  harm,  and  become  dangerous.     To  this  latter  class  belongs 
carbonic  acid  gas. 

29.  Most  of  the  actively  poisonous  gases  have  a  pungent  or 
offensive  odor ;  and,  as  may  be  inferred,  most  repugnant  odors 
indicate  the  presence    of    substances    unfit   for   respiration. 
Accordingly,  as  we  cannot  see  or  taste  these  impurities,  the 
sense  of  smell  is  our  principal  safeguard  against  them.     In  this 
we  recognize  the  forethought  which  has  stationed  this  sense, 
like  a  sentinel,  at  the  proper  entrance  of  the  air-passages,  to 
give  us  warning  of  approaching  harm.     Take,  as  an  example, 
the  ordinary  illuminating  gas  of  cities,  from  which  so  many 
accidents  happen.     How  many  more  deaths  would  it  cause  if, 
when  a  leak  occurs,  we  were  not  able  to  discover  the  escape  of 
the  gas  by  means  of  its  disagreeable  odor.    (Head  Notes  5  and  6.) 

5.  Cleanliness  the  Sum  Total  of  Hygiene.  — "  Disinfectants  have 
the  power  of  destroying  the  cause,  and  of  arresting  the  spread  of  most 
epidemics  and  contagious  diseases,  but  cleanliness  is  the  best  preventive 
of  disease.  Whenever  practicable,  the  abundant  use  of  water  is  better 
than  disinfection.  '  Let  no  one  ever  depend  upon  disinfectants,  fumiga- 
tions, and  the  like,  for  purifying  the  air.  The  offensive  thing,  not  its 
smell,  must  be  removed.'  "  —  Flore nee  Nightingale,  Notes  on  Nursing 
(in  part). 

28.  Importance  of  the  oxygen  in  the  atmosphere  ?    Injurious  character  of  gases  ? 

29.  Pungency  of  gases  ?    The  inference  ?    Our  safeguard  ? 


202  RESPIRATION 

30.  -Organic  matters  exist  in  increased  measure  in  the  ex- 
pired breath  of  sick  persons,  and  impart  to  it,  at  times,  a 
putrid  odor.     This  is  especially  true  in  diseases  which,  like 
typhus  and  scarlet  fever,  are  referable  to  a  blood  poison.     In 
such  cases  the  breath  is  one  of  the  means  by  which  nature 
seeks  to  expel  the  offending  material  from  the  system.     Hence, 
those  who  visit  or  nurse  fever-sick  persons  should  obey  the 
oft-repeated  direction,  "not  to  take  the  breath  of  the  sick." 
At  such  times,  if  ever,  fresh  air  is  demanded,  not  alone  for  the 
sick,  but  also  for  those  who  take  care  of  them.     (See  Care  of 
Sick-Koom,  Appendix.) 

31.  Dust  in  the  Air.  —Attention  has  lately  been  directed  to 
the  dust,  or  haze,  that  marks  the  ray  of  sunshine  across  a 
shaded  room.     Just  as,  many  years  ago,  it  was  discovered  that 
myriads  of  animalcules  were  found  in  the  water  we  drank,  so 
now  the  microscope  reveals  "  the  gay  motes  that  dance  along  a 
sunbeam  "  to  contain  multitudes  of  animal  and  vegetable  forms 
of  a  very  low  grade  —  the  germs  of  fermentation  and  decay, 
and  the  probable  sources  of  disease. 

32.  It  is  found  that  the  best  filter  by  which  to  separate  this 
floating  dust  from  the  air  is  cotton  wool,  although  a  handker- 
chief will  imperfectly  answer  the  same  purpose.     In  a  lecture 

6.  The  True  Prevention  of  Epidemics.  —  "  It  was  in  England  that 
solution  of  the  great  problem  of  hygiene  was  first  attempted.  'Pre- 
ventive Medicine,'  it  is  there  called.  Palmerston  told  a  deputation  which 
waited  on  him  in  order  to  ask  him  to  order  a  fast  on  the  approach  of  the 
second  epidemic  of  cholera,  to  cleanse  their  sewers,  and  diligently  visit 
the  dwellings  of  the  poor.  And  he  did  not  confine  himself  to  good  advice, 
but,  with  his  usual  energy,  he  laid  his  hand  on  sanitary  legislation,  and 
purified  the  air  of  London  and  the  large  manufacturing  towns.  The 
result  of  the  sanitary  measures  carried  out  was  a  reduction  of  the  mor- 
tality of  London  from  26  to  23  per  1,000,  and  in  some  of  the  towns  to  17 
per  1,000  — a  low  death- rate  previously  only  equalled  in  the  Isle  of 
Wight.  More  than  four  thousand  lives  have  been  preserved  yearly  in 
London  ;  and,  assuming  that  the  mortality  among  the  sick  is  1  in  20,  this 
number  represents  a  diminution  in  yearly  sickness  to  the  extent  of  eighty 
thousand."  — Dr.  Joseph  Seegen  in  the  Vienna  Medical  Weekly. 


80.  The  air  of  rooms  in  which  fever-sick  persons  are  confined.? 

31.  Animalcules  in  the  water  ?    Dust  in  the  air  ? 

32.  The  best  air  filter  ?    The  remarks  of  Prof.  Tyndall  ? 


RESPIRATION  203 

on  this  subject  by  Prof.  Tyndall,  he  remarks  that,  "by  breath- 
ing through  a  cotton  wool  respirator,  the  noxious  air  of  the 
sick-room  is  restored  to  practical  purity.  Thus  filtered,  attend- 
ants may  breathe  the  air  unharmed.  In  all  probability,  the 
protection  of  the  lungs  will  be  the  protection  of  the  whole 
system.  For  it  is  exceedingly  probable  that  the  germs  which 
lodge  in  the  air-passages  are  those  which  sow  epidemic  disease 
in  the  body.  If  this  toe  so,  then  disease  can  certainly  be 
warded  off  by  filters  of  cotton  wool.  By  this  means,  so  far  as 
the  germs  are  concerned,  the  air  of  the  highest  Alps  may  be 
brought  into  the  chamber  of  the  invalid." 

33.  Carbonic  Acid  Gas  in  the  Air.  —  We  have  already  spoken 
of  this  gas  as  an  exhalation  from  the  lungs,  and  a  source  of 
impurity ;  but  it  exists  naturally  in  the  atmosphere  in  the  pro- 
portion of  one-half  part  per  thousand.     In  volcanic  regions  it 
is  poured  forth  in  enormous  quantities  from  fissures  in  the 
earth's  surface.     Being  heavier  than  air,  it  sometimes  settles 
into  caves  and  hollows  in  the  surface.     It  is  stated  that  in  the 
island  of  Java,  there  is  a  place  called  the  "  Valley  of  Poison,'7 
where  the  ground  is  covered  with  the  bones  of  birds,  tigers, 
and  other  wild  animals,  which  were  suffocated  by  carbonic  acid 
gas  while  passing  over  it.     The  Lake  Avernus,  the  fabled 
entrance  to  the  infernal  regions,  was,  as  its  name  implies,  bird- 
less,  because  the  birds,  while  flying  over  it,  were  poisoned  by 
the  gas,  and  fell  dead  into  its  waters.     In  mines,  carbonic  acid 
gas  forms  the  dreaded  choke-damp,  while  carburetted  hydrogen 
is  the  fire-damp. 

34.  In  the'  open  air,  men  seldom  suffer  from  carbonic  acid 
gas,  for,  as  we  shall  see  presently,  nature  provides  for  its  rapid 
distribution,  and  even  turns  it  to  a  good  use.     But  its  ill  effects 
are   painfully   evident  in  our  homes,  schools,  and  churches, 
where  it  is  liable  to  collect  as  the  waste  product  of  respiration, 
and  of  that  combustion  which  is  necessary  for  lighting  and 
warming  our  homes.     A  man  exhales,  during  repose,  not  less 
than  one-half  cubic  foot  of  carbonic  acid  gas  per  hour.     A  single 

33.  Carbonic  acid  in  volcanic  regions  ?    In  Java  ?    At  Lake  Avernus  ?    In  mines  ? 

34.  In  the  open  air?    Amount  of  carbonic  acid  exhaled  by  a  man  ?    A  gas-burner?    A 
room  fire  ?    From  furnaces  J 


204  RESPIRATION 

gas-burner  liberates  five  cubic  feet  in  the  same  time,  therefore 
spoiling  about  as  much  air  as  ten  men.  A  fire  burning  in  a 
grate  or  stove  emits  some  impure  gases,  and  at  the  same  time 
abstracts  from  the  air  as  much  oxygen  as  twelve  men  would 
consume  in  the  same  period,  thus  increasing  the  relative 
amount  of  carbonic  acid  gas  in  the  air.  From  furnaces,  as 
ordinarily  constructed,  this  and  other  gases  are  constantly 
leaking  and  poisoning  the  air  of  tightly-closed  apartments. 

35.  Effects  of  Impure  Air.  —  Carbonic  acid  gas,  in  its  pure 
form,  is  irrespirable,  causing  rapid  death  by  suffocation.     Air 
containing  forty  parts  per  thousand  of  this  gas  (the  composition 
of  the  expired  breath)  extinguishes  a  lighted  candle,  and  is 
fatal  to  birds ;  when  containing  one  hundred  parts,  it  no  longer 
yields  oxygen  to  man  and  other  warm-blooded  animals,  and  is, 
of  course,  speedily  fatal  to  them.     In  smaller  quantities,  this 
gas   causes  headache,  labored  respiration,  palpitation,  uncon- 
sciousness, and  convulsions. 

36.  In  crowded  and  badly  ventilated  apartments,  the  air  is 
breathed  over  until  it  contains  from  six  to  ten  times  the  natural 
amount  of  carbonic  acid  gas.     This  contaminated  air  causes 
dullness,  drowsiness,  and  faintness,  because  the  dark,  impure 
blood  circulates  through  the  brain,  oppressing  that  organ,  and 
causing  it  to  act  like  a  blunted  tool.     This  is  a  condition  not 
uncommon  in   our   schools,  churches,  and   court-rooms  —  the 
places  of  all  others  where  it  is  desirable  that  the  mind  should 
be   alert  and  free  to  act;  but,  unhappily,  an  unseen  physio- 
logical cause  is  at  work,  dispensing  weariness  and  stupor  over 
pupils,  audience,  and  juries.     (Head  Notes  1  and  8.) 

7.  The  Ground-Atmosphere  and  its  Relations  to  Dwellings.  —  "The 
soil,  which  naturally  contains  wholesome  air,  and  gives  facility  to  its  every 
movement,  is  not  less  permeable  by  poisonous  gases,  which  are  often  found 
to  pervade  and  issue  from  it.  It  is  easy  to  find  illustrations  of  the  fact 
that  people  are  poisoned  through  the  ground,  since  it  is  almost  a  daily 
occurrence.  Here  is  one,  related  by  an  eminent  authority,  von  Petten- 
kofer:  — 'In  a  residence  at  Augsburg,  apparently  endowed  with  every 
qualification  for  health  and  comfort,  several  priests  lived  together.  On  a 


35.  Effects  of  inhaling  carbonic  acid  alone  ?    In  small  quantities  ? 

36.  Effects  of  the  air  in  crowded  and  badly-ventilated  rooms  ? 


RESPIRATION  205 

37.  Another  unmistakable  result  of  living  in  and  breathing 
foul  air  is  found  in  certain  diseases  of  the  lungs,  especially 
consumption.  For  many  years  the  barracks  of  the  British 
army  were  constructed  without  any  regard  to  ventilation ;  and 
during  those  years  the  statistics  showed  that  consumption  was 
the  cause  of  a  very  large  proportion  of  deaths.  At  last  the 
government  began  to  improve  the  condition  of  the  buildings, 

certain  morning,  one  of  these,  not  the  least  zealous  and  prompt  in  the 
performance  of  his  duties,  was  missed  from  his  usual  post  at  the  matin 
service.  His  colleagues  hurried  back  to  their  common  dwelling  in  search 
of  the  missing  priest,  and  found  him  lying  prostrate  and  insensible  upon 
the  floor  of  his  bed-chamber.  A  doctor  was  immediately  called  in,  and 
at  the  first  sight  of  his  patient,  declared  him  to  be  suffering  from  an  attack 
of  typhus  fever.  The  Sisters  of  Charity,  upon  whom  devolved  the  duty 
of  nursing  him,  and  those  clerical  associates  who  were  active  in  their 
sympathy  and  prompt  to  visit  him  and  give  assistance,  were,  a  few  hours 
after,  attacked  in  the  same  way.  The  doctor  did  not  hesitate  in  his 
diagnosis,  and  pronounced  the  additional  cases  also  typhus  fever.  A 
general  alarm  prevailed  in  the  city,  and  many  called  at  the  house  of  the 
priest,  who  was  greatly  beloved.  Among  others  was  an  old  woman,  who 
discovered  a  strong  smell  of  gas,  and  believing  this  to  be  the  cause  of  the 
sickness,  obtained  permission  to  remove  the  priest  to  her  ownliouse.  The 
priest  had  no  sooner  breathed  the  fresh  air  than  he  began  to  revive,  and 
during  the  very  first  evening  of  his  removal  to  the  new  abode  he  became 
so  much  better  as  to  make  an  importunate  demand  for  food.  He  soon 
got  entirely  well.  The  old  woman,  thus  confirmed  in  her  gas  theory,  and 
eager  to  save  the  remaining  patients,  who  had  continued  to  increase  in 
number  in  the  priests'  house,  now  had  an  interview  with  the  manager 
of  the  gas-works  which  supplied  the  town,  and  prevailed  upon  him  to 
investigate  the  condition  of  the  gas-pipes  in  the  vicinity  of  the  priests' 
residence.  This  was  done,  and  a  leak  from  which  the  gas  was  escaping 
into  the  ground  was  found  and  stopped.  The  air  of  the  house  was  per- 
ceived at  once  to  improve,  and  with  it  the  health  of  the  patients  that  were 
not  removed ;  these  finally  completely  recovered  from  what  the  doctor  even 
was  compelled  to  admit  was  not  typhus  fever,  but  poisoning  by  gas.'  "  — 
The  Book  of  Health. 

8.  Pure  Air  and  Good  Morals.  —  "Cleanliness  and  self-respect  go  to- 
gether, and  it  is  no  paradox  to  affirm  that  you  tend  to  purify  men's 
thoughts  and  feelings  when  you  purify  the  air  they  breathe.  *  *  *  * 
With  a  low  average  of  popular  health  you  will  have  a  low  average  of 
national  morality,  and  probably  also  of  national  intellect.  Drunkenness 
and  vice  of  other  kinds  will  flourish  in  such  a  soil,  and  you  cannot  get 
healthy  brains  to  grow  on  unhealthy  bodies."  —  Lord  Derby. 


87.  A.  cause  of  consumption  ?    How  was  the  fact  illustrated  ? 


206  RESPIRATION 

giving  larger  space  and  air-supply;  and  as  a  consequence, 
the  mortality  from  consumption  has  diminished  more  than 
one-third. 

38.  The  lower  animals  confined  in  the  impure  atmosphere 
of  menageries,  contract   the   same   diseases   as  man.     Those 
brought  from  a  tropical  climate,  and  requiring  to  be  closely 
housed,   generally   die    of    consumption.      In    the   Zoological 
Gardens  of  Paris,  this  disease  affected  nearly  all  monkeys, 
until  care  was  taken  to  introduce  fresh  air  by  ventilation,  and 
then  it  almost  wholly  disappeared.     The  tendency  of  certain 
occupations  to  shorten  life  is  well  known,  disease  being  occa- 
sioned by  the  fumes  and  dust  which  arise  from  the  materials 
employed,  in  addition  to  the   bad   air  of  the  workshop  or 
factory,  where  many  hours  are  passed- daily.     (Read  Note  9.) 

39.  The  following  table  shows  the  comparative  amount  of 
carbonic  acid  gas  in  the  air  under  different  conditions,  and  the 
effects  sometimes  produced : 

PROPORTION  OF  CARBONIC  ACID  GAS.  In  1000  parts  of  Air. 

Air  of  country 4 

Air  of  city 5 

In  hospital,  well  ventilated 6 

In  school,  church,  etc.,  fairly  ventilated     .     .     .       1.2  to    2.5 
In  court-house,  factory,  etc.,  without  ventilation       4.    to  40. 

In  bed-room,  before  being  aired 4.5 

In  bed-room,  after  being  aired 1.5 

Constantly  breathed,  causing  ill  health  ....  2. 
Occasionally  breathed,  causing  discomfort  ...  3. 
Occasionally  breathed,  causing  distress  ....  10. 

Expired  air 40. 

Air  no  longer  yielding  oxygen 100. 

9.  Consumption  is  Lung  Starvation. —  "  The  practice  of  allowing  the 
lungs  only  improper  food,  in  the  form  of  vitiated  air,  is  one  of  the  most 
prevalent  habits  of  civilized  life,  and  diseases  of  the  lungs  are  its  greatest 
bane  and  greatest  dread.  More  persons  die  by  consumption  than  by  any 
other  single  disease.  If  there  be  added  to  those  the  large  number  that 
perish  every  year  by  inflammation  of  the  lungs  and  bronchial  tubes,  disease 
and  premature  death  may  be  well  said  to  have  in  these  organs  their  chief 


38.  How,  in  the  case  of  the  lower  animals  ?    Tendency  of  certain  occupations  ? 

39.  Give  the  fact  &»  set  forth  in  the  table. 


RESPIRATION  207 

40.  Nature's  Provision  for  Purifying  the  Air. — "VVe  have  seen 
that  carbonic  acid  gas  is  heavier  than  air,  and  irrespirable. 
Why,  then,  does  it  not  sink  upon  and  overwhelm  mankind 
with  a  silent,  invisible  wave  of  death?  Among  the  gases 
there  is  a  more  potent  force  than  gravity,  which  forever  pre- 
vents such  a  tragedy.  It  is  known  as  the  diffusive  power  of 
gases.  It  acts  according  to  a  definite  law,  and  with  a  resist- 
less energy  compelling  fhese  gases,  when  in  contact,  to  mingle 
until  they  are  thoroughly  diffused.  The  added  influence  of 
the  winds  i$  useful,  by  insuring  more  rapid  changes  in  the  air, 
air  in  motion  being  perfectly  wholesome.  The  rains  also  wash 
the  air. 

citadel.  The  leading  cause  of  all  this  is,  undoubtedly,  the  poor  quality 
of  the  food  on  which  the  lungs  are  nurtured.  The  very  best  physicians, 
when  their  attention  is  directed  to  the  subject,  admit  the  full  force  of 
this  conclusion*  and  that  it  has  not  received  the  attention  it  deserves. 
Prof essor  Hartshorne  remarks  on  this  point,  that  '  the  influence  of 
impure  air  in  promoting  consumption  has  probably  heretofore  been 
underrated.'  'The  vitiated  air  of  the  European  barrack  system  for 
soldiers,'  says  Professor  Parkes,  'is  the  only  way  in  which  the  great 
prevalence  of  consumption  in  European  armies  can  be  accounted  for.' 
This  is  the  conclusion  to  which  the  Sanitary  Commissioners  for  the  army 
came»  in  their  celebrated  report :  '  A  great  amount  of  phthisis  (con- 
sumption) has  prevailed  in  the  most  varied  stations  of  the  army  and  in 
the  most  beautiful  climates  —  in  Gibraltar,  Malta,  Ionia,  Jamaica,  Trini 
dad,  Bermuda,  etc.  —  in  all  of  which  places  the  only  common  condition 
was  the  vitiated  atmosphere  which  our  barrack  system  everywhere  pro- 
duced. Andr  as  if  to  clinch  the  argument,  there  has  been  of  late  years  a 
most  decided  decline  in  phthisis  in  these  stations,  while  the  only  circum- 
stance which  has  notably  changed  in  the  time  has  been  the  condition  of 
the  air.'  A  very  eminent  authority,  the  late  Dr.  Marshall  Hall,  of  Eng- 
land,, said,  in  reference  to  pure'  air  in  the  treatment  of  consumption,  '  If 
I  were  seriously  ill  of  consumption,  I  would  live  out  doors  day  and 
night,  except  in  rainy  weather,  or  midwinter ;  then  I  would  sleep  in 
an  unplastered  log  house.  Physic  has  no  nutriment,  gaspings  for  air 
cannot  cure  you,  monkey  capers  in  a  gymnasium  cannot  cure  you,  and 
stimulants  cannot  cure  you.  What  consumptives  want  is  pure  air,  not 
physic  —  pure  air,  not  medicated  air  —  plenty  of  meat  and  bread.  *  Let 
it  be  remembered,  in  this  connection,  that  every  hygienic  or  health-pro- 
moting measure  which  tends  to  cure  a  disease  is  much  more  efficacious  in 
preventing  it."  —  Black's  Ten  Laws  of  Health. 


40.  What  can  you  state  of  the  diffusive  power  of  gases  ?    The  added  influence  of  the 
winds? 


208  RESPIRATION 

41.  Oxidation.  —  When  a  substance  capable  of  undergoing 
chemical  changes  unites  with  oxygen,  it  is  said  to  oxidize. 
This  process  of  oxidation  is  always  accompanied  by  the  pro- 
duction of  heat.     As  an  example,  when  coal  is  burned,  its 
carbon  and  other  component  parts  unite  with  oxygen  and  form 
new  chemical  compounds,  thus  producing  a  great  deal  of  heat. 
The  chemical  processes  going  on  during  the  burning  of  coal 
set  free  a  certain  amount  of  energy,  which  is  utilized  in  the 
production  of  steam  and  other  'kinds  of  power.     Thus,  in  an 
analogous  manner,  do  the  chemical  processes  going  on  con- 
stantly in  our  body  by  the  aid  of  the  oxygen  produce  heat  and 
energy.     (Head  Note  15.) 

42.  In  the  sea,  as  in  the  air,  the  same  circle  of  changes  is 
observed.     Marine  animals  consume  oxygen  and  give  off  car- 
bonic acid  gas,  while  marine  plants  consume  carbonic  acid  gas, 

10.  Plants  and  the  Air.  —  "  Though  the  air  is  dependent  for  the  renewal 
of  its  oxygen  on  the  action -of  the  green  leaves  of  plants,  it  must  not  be 
forgotten  that  it  is  only  in  the  presence  and  under  the  stimulus  of  light 
that  these  organisms  decompose  carbonic  acid  gas.  All  plants,  irrespec- 
tive of  their  kind  or  nature,  absorb  oxygen  and  exhale  carbonic  acid  gas 
in  the  dark.  The  quantity  of  noxious  gas  thus  eliminated  is,  however, 
exceedingly  small  when  compared  with  the  oxygen  thrown  out  during  the 
day.  Aside  from  the  highly  deleterious  action  that  plants  may  exert  on 
the  atmosphere  of  a  sleeping-room,  by  increasing  the  proportion  of  car- 
bonic acid  gas  during  the  night,  there  is  another  and  more  important 
objection  to  be  urged  'against  their  presence  in  such  apartments.  Like 
animals,  they  exhale  peculiar  volatile  organic  principles,  which^in  many 
instances  render  the  air  unfit  for  the  purposes  of  respiration.  Even  in 
the  days  of  Andronicus  this  fact  was  recognized,  for  he  says,  in  speaking 
of  Arabia  Felix,  that. 'by  reason  of  myrrh,  frankincense,  and  hot  spices 
there  growing,  the  air  was  so  obnoxious  to  their  brains,  that  the  very 
inhabitants  at  some  times  cannot  avoid  its  influence.'  What  the  influence 
on  the  brains  of  the  inhabitants  may  have  been  does  not  at  present  interest 
us  ;  we  have  only  quoted  the  statement  to  show  that  long  ago  the  emana- 
tions from  plants  were  regarded  as  having  an  influence  on  the  condition 
of  the  air ;  and,  in  view  of  our  present  ignorance,  it  would  be  wise  to  banish 
them  from  our  sleeping  apartments,  at  least  until  we  are  better  informed 
regarding  their  true  properties."  —  Draper  on  Poisoned  Air. 


41.  How  is  the  constant  purity  of  the  air  secured  ?    Explain  the  process. 

42.  What  process  occurs  in  the  sea  ?    How  is  the  fact  illustrated  ? 


RESPIRATION 


209 


and  liberate  oxygen.  Taking  advantage  of  this  fact,  we  may 
so  arrange  aquaria  with  fishes  and  sea-plants,  in  their  proper 
combinations,  that  each  may  supply  the  needs  of  the  other, 
and  the  water  may  seldom  require  to  be  renewed.  This  affords 
us,  on  a  small  scale,  an  illustration  of  the  grand  circle  of 
changes  taking  place  in  the  air  about  us,  and  also  of  the  har- 
monious dependence  of  the  two  great  kingdoms  of  nature. 

43.  Ventilation.  —  Since  Hhe   external   atmosphere,  as   pro- 
vided by   nature,  is   always  pure,  and  since  the   air  in  our 
dwellings   and  other  buildings   is  almost  always  impure,  it 
becomes  imperative  that  there  should  be  a  free  communication 
from  the  one  to  the  other.     This  we  aim  to  accomplish  by  venti- 
lation.    As  our  houses  are  ordinarily  constructed,  the  theory  of 
ventilation,  "  to  make  the  internal  as  pure  as  the  external  air," 
is  seldom  carried  out.     Doors,  windows,  and  flues,  the  natural 
means  of  replenishing  the  air,  are  too  often  closed,  almost 
hermetically,  against 

the  precious  element. 
Special  means,  or  spe- 
cial attention,  must 
therefore  be  used  to  se- 
cure even  a  fair  supply 
of  fresh  air.  This  is 
still  more  true  of  those 
places  of  public  resort, 
where  large  numbers 
of  persons  are  crowded 
together.  (See  House- 
Drainage,  Appendix.) 

44.  If  there  are  two 
openings  in  a  room,  one 
as  a  vent  for  foul  air, 
and  the  other  an  inlet 
for  atmospheric  air,  and 
if  the  openings  be  large 


FIG.  58.  —  Showing  manner  of  ventilating  by  inserting 
strip  of  wood  beneath  lower  sash  of  window 


48.   Character  of  the  external  air  ?    Of  the  air  in  our  dwellings  ?    What  becomes  impera- 
tive ?     Imperfect  ventilation  of  our  dwellings  ? 

44.    What  hints  are  given  for  the  ventilation  of  our  dwellings  ? 


210  RESPIRATION 

in  proportion  to  the  number  of  air  consumers,  the  principal 
object  will  be  attained.  Thus,  a  door  and  window,  each  open- 
ing into  the  outer  air,  will  ordinarily  ventilate  a  small  apart- 
ment ;  or  a  window  alone  will  answer,  if  it  be  open  both  above 
and  below,  and  the  open  space  at  each  end  be  not  less  than  one 
inch  for  each  occupant  of  the  room,  when  the  window  is  about 
a  yard  wide.  The  direction  of  the  current  is  generally  from 
below  upward,  since  the  foul,  heated  air  tends  to  rise ;  but  this 
is  not  essential.  *  Its  rate  need  not  be  rapid ;  a  "  draught," 
or  perceptible  current,  is  never  necessary  to  good  ventilation. 
The  temperature  of  the  air  admitted  may  be  warm  or  cold.  It 
is  thought  by  many  that  if  the  air  is  cold,  it  is  pure ;  but  this 
is  an  error,  since  cold  air  will  receive  and  retain  the  same 
impurities  as  warm  air. 

45.  Shall  we  open  our  bed-rooms  to  the  night  air  ?  Florence 
Nightingale  says,  in  effect,  that  night  air  is  the  only  air  we 
can  then  breathe.  "  The  choice  is  between  pure  air  without 
and  impure  air  within.  Most  people  prefer  the  latter  —  an 
unaccountable  choice.  An  open  window,  most  nights  in  the 
year,  can  hurt  no  one.  In  great  cities,  night  air  is  the  best 
and  purest  to  be  had  in  twenty-four  hours.  I  could  better 
understand,  in  towns,  shutting  the  windows  during  the  day 
than  during  the  night."  (Read  Note  11.) 

*  When  the  window  is  of  the  common  sash  kind,  a  good  supply  of 
fresh  air  may  be  obtained  without  a  current,  by  placing  a  strip  of  board 
about  four  inches  wide  under  the  lower  sash  (Fig.  53).  The  window  is 
thus  closed  'against  rain  and  snow,  but  allows  of  a  supply  of  fresh  air  to 
enter  between  the  sashes.  If  still  more  ventilation  is  needed  to  keep  the 
air  of  the  room  sweet,  the  same  arrangement  may  be  made  at  the  top  of 
the  window. 

11.  Pure  Air  in  our  Homes  during  Cold  Weather.  —  "Fresh  air  is  the 
great  natural  disinfectant,  antiseptic,  and  purifier,  and  not  to  be  com- 
pared for  a  moment  with  any  of  artificial  contrivance.  There  is  plenty  of 
it  in  the  world ;  yet,  disguise  the  fact  as  we  may,  there  is  no  getting  over 
the  unwelcome  truth,  that  to  provide  it  in  abundance  in  our  climate  is 
expensive,  since  during  seven  months  in  the  year  it  must  be  artificially 
warmed,  in  order  that  our  homes  may  be  comfortable.  To  take  in  air  at 
the  average  winter  temperature  of  28°,  raise  it  to  68°,  and  discharge  it 


46.  State  what  Florence  Nightingale  says  about  inhaling  night  air. 


RESPIRATION  211 

46.  Animal  Heat.  —  Intimately  connected  with  respiration  is 
the  production  of  animal  heat,  or  the  power  of  maintaining  the 
temperature  of  the  body  above  that  of  the  medium  in  which 
the  creature  moves ;  thus,  the  bird  is  warmer  than  the  air,  and 
the  fish  than  the  water.     This  elevation  of  temperature  is  the 
result  of  the  various  chemical  changes  which  are  constantly 
taking  place  in  the  system.     Although  common  to  all  animals, 
in  a  greater  or  less  degree^heat  is  not  peculiar  to  them,  since 
plants  also  generate  it,  especially  at  the  time  of  sprouting  and 
flowering.    If  a  thermometer  be  placed  in  a  cluster  of  geranium 
flowers,  it  will  indicate  a  temperature  several  degrees  above 
that  of  the  surrounding  air. 

47.  Among  animals  great  differences   are   noticed  in  this 
respect,  but  the  degree  of  heat  produced  is  always  proportional 
to  the  activity  of  respiration  and  the  amount  of  oxygen  con- 
sumed.    Accordingly,  the  birds,  whose  habits  are  extremely 
active,  and  whoss  breathing  capacity  is  the  greatest,  have  uni- 
formly the  highest  temperature.     Sluggish   animals,  on  the 
contrary,  as  frogs,  lizards,  and  snakes,  have  little  need  for 
oxygen,  and  have  incompletely  developed  lungs ;  these  animals 
are  cold  to  the  touch  —  that  is,  they  have  relatively  a  lower 
temperature  than  man,  and  their  positive  temperature  is  but 
little  above  that  of  the  external  air.     Accordingly,  zoologists 
have  so  arranged  the  animal  kingdom  that  warm-blooded  ani- 
mals, including  man,  the  birds,  and  the  quadrupeds,  are  classi- 
fied together ;  while  the  coldblooded  animals,  such  as  the  fish, 
tortoise,  frog,  and  all  that  have  no  vertebral  column,  are  classed 
by  themselves. 

again  from  our  houses  even  once  in  an  hour,  is  a  process  which  cannot  be 
accomplished  without  paying  roundly  ;  yet  on  no  other  condition  can  we 
reasonably  expect  health  and  long  life.  The  best  way  is  to  freely  admit 
that  it  is  expensive,  but  worth  the  money  it  costs.  If  Benjamin  Franklin 
thought  that  'a  penny  saved  is  a  penny  earned,'  he  is  equally  sure  that 
4  health  is  wealth.'  "  —  George  Derby  on  the  Prevention  of  Disease. 


46.  Warmth  of  the  bird  as  compared  with  that  of  the  air  ?    Of  the  fish  and  the  water  ? 
Heat  in  animals  and  plants  ?    How  illustrated  with  the  thermometer  ? 

47.  Amount  of  heat  in  animals,  how  apportioned  f    As  regards  the  birds  ?    Frogs,  and 
other  sluggish  animals  ?    Arrangement  made  by  zoologists  ? 


212  RESPIRATION 

48.  The  temperature  of  the  human  body  is  about  100°  Fah- 
renheit, and  Remains  about  the  same  through  winter  and  sum- 
mer—  in  the  tropics  as  well  as  in  the  frozen  regions  of  the 
north.     It  may  change  temporarily  within  the  range  of  about 
twelve  degrees ;  but  any  considerable,  or  long-continued  eleva- 
tion or  diminution  of  the  bodily  heat  is  certain  to  result  dis- 
astrously. 

49.  Man  is  able  to  adapt  himself  to  all  extremes  of  climate ; 
and,  in  fact,  by  means  of  clothing,  shelter,  and  food,  is  able  to 
create  for  himself  an  artificial  climate  wherever  he  chooses  to 
reside.     The  power  to  resist  cold  consists  chiefly  in  prevent- 
ing the  heat  which   is   generated  by  the  vital   processes  of 
the  body  from  being  lost  by  radiation.     Warm  clothing,  such 
as  we  wear  in  winter,  has,  in  reality,  the  same  temperature  as 
that  which  is  worn  in  summer ;  but,  by  reason  of  being  thick 
and  porous,  it  is  a  bad  conductor  of  heat,  and  thus  prevents  the 
escape  of  that  produced  by  the  body.     If  woollen  fabrics  were 
intrinsically  warm,  no  one  would  wrap  a  piece  of  flannel,  or 
blanket,  around  a  block  of  ice  to  prevent  its  melting  in  sum- 
mer. 

50.  The  faculty  of  generating  heat  explains  how  it  is  that 
we  are  enabled  to  resist  the  effects  of  cold ;  but  how  does  the 
body  withstand  a  temperature  higher  than  its  own  ?    Men  have 
been  know  to  remain  several  minutes  in  an  atmosphere  heated 
above  the  boiling-point  of  water,  and  yet  the  temperature  of 
their  own  bodies  was  not  greatly  increased.     Those  who  labor 
in  foundries  and  glass-works  are  habitually  subjected  to  very 
high  degrees  of  temperature,  but  they  do  not  suffer  in  health 
more  than  those  engaged  in  many  other  occupations. 

51.  The  regulation  of  the  temperature  of  the  body  is  effected 
by  means  of  perspiration,  and  by  its  evaporation.     So  long  as 
the  skin  acts  freely,  and  the  air  freely  absorbs  the  moisture, 
the  heat  of  the  body  does  not  increase,  for  whenever  evapora- 

48.  State  what  is  said  respecting  the  temperature  of  the  human  body. 

49.  Ability  of  man  to  adapt  himself  to  different  climates?    In  what  does  the  power  to 
resist  cold  consist  ?    What  is  said  about  warm  clothing  ? 

50.  Men  in  an  atmosphere  above  the  boiling-point  ?     In  foundries  and  glass- works  ? 

51.  The  regulation  of  .the  temperature  of  the  body.     Give  the  explanation. 


RESPIRATION  213 

tion  takes  place,  it  is  attended  with  the  abstraction  of  heat  — 
that  is,  the  part  becomes  relatively  colder.  This  may  be  tested 
by  moistening  some  part  of  the  surface  with  cologne,  ether,  or 
other  volatile  liquid,  and  then  causing  it  to  evaporate  rapidly 
by  fanning.  The  principle  that  evaporation  produces  cold  has 
been  ingeniously  and  practically  employed,  in  the  manufacture 
of  ice  by  means  of  freezing  machines. 

52.  Spontaneous  Combustion  —  Alcohol  the  Indirect  Cause.  — 
Is  it  possible  that  the  temperature  of  the  living  body  can  be  so 
increased  that  its  tissues  will  burn  spontaneously  ?     From  time 
to  time  cases  have  been  reported  in  which,  by  some  mysterious 
means,  considerable  portions  of  the  human  body  have  been 
consumed,  apparently  by  fire  —  the  victim  being  found  dead,  or 
incapable  of  explaining  the  occurrence.     Hence,  the  theory  has 
been  current  that,  under  certain  conditions,  the  tissues  of  the 
body  might  become  self-ignited ;  and  the  fact  that  this  so-called 
spontaneous  combustion  has  ordinarily  taken  place  in  those  who 
had  been  addicted  to  the  use  of  alcoholic  drinks,  has  given  a 
color  of  probability  to  the  opinion.     It  has  been  supposed  that 
the  flesh  of  these  unfortunate  persons,  becoming  saturated  with 
alcohol  thus  taken  into  the  system,  took  fire  upon  being  ex- 
posed to  a  flame,  as  of  a  lighted  candle,  or,  indeed,  without  any 
external  cause.    But,  whether  this  be  possible  or  not,  one  thing 
is  certain  —  this  strange  kind  of  combustion  has  never  been 
actually  witnessed  by  any  one  competent  to  give  a  satisfactory 
account  of  it. 

53.  The  results  that  have  been  observed  may  be  satisfacto- 
rily explained  by  the  accidental  ignition  of  the  clothes,  or  other 
articles  near  the  body,  and  by  the  supposition  that  the  indi- 
vidual was  at  the  time  too  much  stupefied  by  intoxication  to 
notice  the  source  of  danger  and  provide  for  his  safety.     The 
highest  temperature  that  has  been  observed  in  the  body  — 
about  112°  Fahrenheit  —  is  too  low  to  ignite  the  vapor  of  alco- 
hol ;  much  less  will  it  cause  the  burning  of  animal  tissues.     It 
is  undoubtedly  true  that  when  the  tissues  are  filled  with  alco- 

52.   State  what  is  said  of  spontaneous  combustion. 
58.   How  is  the  theory  refuted  1 


214  RESPIRATION 

hoi,  combustion  will  more  easily  take  place  than  when  the  body 
is  in  a  normal  state ;  but,  under  any  condition,  the  combustion 
of  the  body  requires  a  higher  degree  of  heat  than  can  be  gener- 
ated by  the  body  itself,  or  the  mere  proximity  of  a  lighted 
candle,  or  any  cause,  of  similar  character. 

54.  The  Effect  of  Alcohol  upon  Respiration.  —  Whenever  wine, 
or  any  other  form  of  alcoholic  drink,  is  taken  into  the  stomach, 
it  is  quite  rapidly  absorbed  into  the  blood-current,  and  in  a  few 
minutes   it  imparts   to  the  breath  a  peculiar,  offensive  odor. 
This  is  due  to  the  vapor  of  alcohol  that,  little  by  little,  is  ex- 
pelled from  the  body,  along  with  the  carbonic  acid  gas  exhaled 
through  the  lungs.    If  the  quantity  of  drink  taken  has  been  con- 
siderable, this  disagreeable  odor  may  continue  a  day  or  more. 

This  condition  is  evidence  that  an  unnatural  labor  has  been 
thrown  upon  the  lungs  ;  namely,  it  is  an  effort  on  the  part  of 
the  general  system  to  get  rid  of  a  poison  that  is  hurtful  to  every 
organ  by  which  it  is  retained.  WJiile  this  exhalation  of  alco- 
holic vapor  continues,  the  respiratory  act  is  impaired,  for  not 
only  can  less  carbonic  acid  gas  be  thrown  off,  but  there  is  also 
a  diminished  inhalation  of  oxygen. 

55.  Respiratory  Diseases  among  the  Intemperate.  —  The  struc- 
ture of  the  respiratory  organs  is  such  that  they  are  relatively 
tolerant  of  the  presence  of  alcohol  in  the  body. 

Wheezy  breathing  and  hoarseness  of  voice  are  noticeable 
among  inebriates ;  but  this  class  does  not  suffer  greatly  from 
severe  attacks  of  lung  diseases  that  can  be  said  to  be  directly 
due  to  the  liquor  they  drink.  Indirectly,  however,  they  suffer 
greatly,  as  a  class,  from  those  diseases,  because  they  incur  ex- 
posures of  every  imaginable  variety,  while  under  the  intoxicant 
influence  of  this  powerful  drug,  which  can,  according  as  it  is 
taken  in  less  or  greater  quantity,  deprive  a  person  of  his  sober 
self-management  or  bring  him  down  to  utter  loss  of  conscious- 
ness. It  is  in  this  way  that  the  users  of  alcohol  fall  a  prey, 
especially  in  the  winter  season,  to  attacks  of  pneumonia,  or 
lung  fever,  and  other  serious  disease  of  the  respiratory  organs. 

54.  Does  alcohol  appear  in  the  breath  ?    Does  it  interfere  with  respiration  ? 
65.   What  respiratory  diseases  among  the  intemperate  ? 


RESPIRATION 


215 


TOPICAL    OUTLINE 


TRACHEA .  . 


LARYNX 


LUNGS 


EXPIRATION 


CHANGES 


Structure  . 


Rings.  .  .  . 
Bronchi  .  .  . 

Bronchial 
tubes 


Cartilaginous  rings. 
Fibrous  tissue. 

Lined  with  ciliated  epithelium. 
C-shaped. 

Complete  in  front.    Incomplete  behind- 
Connected  by  fibrous  tissue. 
Right  and  left. 

In  structure  similar  to  trachea. 
Rings  of  cartilage  very  imperfect. 
Cartilage  disappears    in   smallest    tubes, 
which  terminate  in  groups  of  air-cells. 


Two  rings 


Contains 


f  ThyroW  cartiUge 

I  Cricoid  cartilage  —  A  complete  ring. 

j  Vocal  cords. 

i  Epiglottis  —  Closes  the  glottis. 
Right  .....        Three  lobes. 
Left    . 


INSPIRATION 


Two  lobes. 

(Air-vessels —     Bronchial  tubes  and  cells, 
f  Pulmonary  arteries. 
Blood-vessels  \  Capillaries. 

[  Pulmonary  veins. 
External  intercostals  contract. 

Raise  the  ribs. 

Chest  enlarged  \      Make  the  chest  wider. 
Diaphragm  depressed. 

Chest  made  deeper. 
Lungs  expand  with  the  chest. 

Air  rushes  in  through  the  trachea,  filling  the  enlarged  lungs 
Elastic  walls  of  the  thorax  recoil. 
Elastic  lungs  recoil. 
Internal      intercostals    con- 
tract. 

Chest  Ribs  depressed, 

made  Chest  becomes  narrower, 

smaller  Diaphragm  raised. 

Chest  made  shallower. 
Abdominal  muscles  contract. 
Abdominal  organs  press  on 
underside  of  diaphragm. 
Air  forced  out  through  the  trachea. 
(  Loses  —  Oxygen. 

Carbon  dioxide. 


Forced 
expiration. 


Of  air 


Blood 


Gains 


(  In  lungs 


In  tissues 


Water  vapor. 

Other  waste  matters. 

!  Carbon  dioxide. 
Water. 
Other  waste  matter 
Gains  — Oxygen. 
Loses  — Oxygen. 

Carbon  dioxide. 
Gains  \  Waste  matter  in  so- 
lution. 


216  RESPIRATION 


QUESTIONS    FOR   TOPICAL   REVIEW 

PAGE 

1.  What  is  the  object  of  respiration  ? 187 

2.  What  are  the  special  organs  of  respiration  ? 187 

3.  In  what  organs  does  a  change  in  the  blood  take  place  ? 187 

4.  What  is  the  nature  of  the  change ?. .' i  187 

5.  Where  are  the  lungs  situated,  and  what  is  the  character  of  the  sub- 

stance of  which  they  are  composed  ? 187,  188 

6.  Describe  the  facilities  provided  for  the  lung  movements 188 

7.  Describe  the  trachea,  or  windpipe 188-191 

8.  Describe  the  bronchial  tubes,  and  their  uses 189 

9.  What  can  you  state  in  relation  to  the  epiglottis  ? 190 

10.  What  are  the  cilia,  and  what  use  do  they  probably  serve  ? 191 

11.  How  may  the  lungs  be  affected  by  not  being  properly  protected  ?  . .      192 

12.  Describe  the  movements  necessary  to  the  act  of  perfect  respiration  .  192,  193 

13.  What  is  the  diaphragm,  and  what  is  its  office  ? 192 

14.  How  may  the  organs  of  respiration  be  so  improved  as  to  increase 

their  capacity  and  power  ? 192 

15.  What  is  stated  in  relation  to  the  frequency  of  respiration  ? 193 

16.  To  what  extent  may  the  act  of  respiration  be  subjected  to  our  wills  ?.  194 

17.  What  may  be  said  to  be  the  capacity  of  the  lungs  ? 194 

18.  How  long  does  it  take  every  particle  of  air  in  the  lungs  to  be  expelled 

and  new  air  to  take  its  place  ? 194 

19.  What  would  be  the  consequences,  if  the  entire  capacity  of  the  lungs 

were  constantly  used  ? 194,  195 

20.  What  would  be  the  consequences  to  a  fish  put  into  water  from  which 

the  air  had  been  completely  exhausted  ?    Why  ? 195 

21.  What  is  the  air,  and  what  are  its  parts  ? 195,  196 

22.  What  is  the  character  of  the  air  that  has  been  just  breathed  ? 196 

23.  Why  is  it  that  such  air  is  not  fit  for  respiration  ? 196-198 

24.  What  are  the  effects,  as  recorded  in  notable  cases  of  confinement  in     ' 

places  the  air  of  which  has  been  breathed  "  over  and  over  "  ?  . .  197,  198 

25.  What  can  you  state  of  changes  in  the  blood  from  respiration  ? 198 

26.  What  of  the  air  as  an  article  of  food  ? 198,  199 

27.  What  on  the  subject  of  interchange  of  gases  in  the  lungs  ? 199 

28.  Explain  the  difference  between  arterial  and  venous  blood 199,  200 

29.  Explain,  if  you  can,  the  cause  of  the  difference 200 

30.  State  what  you  can  in  relation  to  blue  blood 200 

31.  In  relation  to  the  amount  of  labor  exerted  in  respiration 200,  201 

32.  In  relation  to  the  deleterious  properties  of  different  gases 201 

33.  In  relation  to  the  dust  that  floats  in  the  air • 202 

34.  What  are  the  properties  of  carbonic  acid  gas  ? 203,  204 

35.  In  what  places  is  carbonic  acid  gas  commonly  found  ? 204 

36.  Describe  the  effects  of  carbonic  acid  gas 204 

37.  What  are  the  general  effects  of   breathing    any  impure  atmos- 

phere ?  204-206 

38.  What  are  Nature's  provisions  for  purifying  the  air? 207-209 

39.  What  hints  and  directions  are  given  on  the  subject  of  ventilation  ?.  209,  210 

40.  How  does  the  temperature  of  the  body  compare  with  the  medium  in 

which  it  lives? » 212 

41.  How  is  temperature  of  the  body  regulated  and  sustained  ? 212,  213 

42.  State  what  you  can  on  the  subject  of  spontaneous  combustion 213 


CHAPTER  IX 

THE*  NERVOUS   SYSTEM 

Animal  and  Vegetative  Functions  —  Sensation,  Motion,  and  Volition  — 
The  Structure  of  the  Nervous  System  — The  White  and  Gray  Sub- 
stances —  The  Brain  —  Its  Convolutions  —  The  Cerebellum  —  The 
Spinal  Cord  and  its  System  of  Nerves  —  The  Anterior  and  Posterior 
Hoots  —  The  Sympathetic  System  of  Nerves  —  The  Properties  of  Ner- 
vous Tissue*— Excitability  of  Nervous  Tissues  —  The  Functions  of  the 
Spinal  Nerves  and  Cord  —  The  Direction  of  the  Fibres  of  the  Cord  — 
Reflex  Activity,  and  its  Uses— The  Functions  of  the  Medulla  Oblon- 
gata  and  the  Cranial  Ganglia  —  The  Eeflex  Action  of  the  Brain  — 
Effects  of  Alcohol,  Tobacco,  Snuff,  Narcotics,  Opium,  Chloral,  Hash- 
eesh, Chloroform 

1.  Animal  Functions. — The  vital  processes  which  we  have 
been  considering  in  the  three  previous  chapters  —  of  digestion, 
circulation,  and  respiration  —  belong  to  the  class  of  functions 
known  as  vegetative  functions.  That  is,  they  are  common  to 
vegetables  as  well  as  animals ;  for  the  plant,  like  the  animal, 
can  originate  nothing,  not  even  the  smallest  particle  of  matter ; 
and  yet  it  grows,  blossoms,  and  bears  fruit,  by  reason  of  obtain- 
ing and  digesting  the  nutriment  which  the  air  and  soil  provide. 
The  plant  has  its  circulatory  fluid  and  channels,  by  which  the 
nutriment  is  distributed  to  all  its  parts.  It  has,  also,  a  curious 
apparatus  in  its  foliage,  by  which  it  abstracts  from  the  air 
those  gaseous  elements  so  necessary  to  its  support ;  and  thus  it 
accomplishes  vegetable  respiration.  These  vegetative  functions 
have  their  beginning  and  end  within  the  organism  of  the  plant ; 
and  their  object  is  the  preservation  of  the  plant  itself,  as  well 
as  of  the  entire  species. 


1.  What  processes  are  known  as  the  vegetative  functions?    Why  so  called?    What 
properties  and  functions  does  the  plant  possess  ?    Their  object  T 

217 


218  THE  NERVOUS  SYSTEM 

2.  The  animal,  in  addition  to  these  vegetative  functions,  has 
another  set  of  powers,  by  the  use  of  which  he  becomes  con- 
scious of  a  world  external  to  himself,  and  brings  himself  into 
active  relations  with  it.     By  means  of  the  vegetative  processes, 
his  life  and  species  are  maintained ;  while,  by  means  of  certain 
animal  functions,  he  feels,  acts,  and  thinks.     These  functions, 
among  which  are  sensation,  motion,  and  volition,  not  only  dis- 
tinguish the  animal  from  the  plant,  but,  in  proportion  to  their 
development,  elevate  one  creature  above  another ;  and  it  is  by 
virtue  of  his  pre-eminent  endowment,  in  these  respects,  that 
man  holds  his  position  at  the  head  of  the  animal  creation. 

3.  Among   animals   whose   structure   is  very  simple  —  the 
hydra,  or  fresh-water  polyp,  being  an  example  —  no  special 
organs  are  empowered  to  perform  separate  functions,  but  every 
part  is  endowed  alike ;  so  that,  if  the  animal  be  cut  into  pieces, 
each  portion  has  all  the  properties  of  the  entire  original ;  and, 
if  the  circumstances  be  favorable,  each  of  the  pieces  will  soon 
become  a  complete  hydra.     As  we  approach  man,  in  the  scale 
of  beings,  we  find  that  the  organs  multiply,  and  the  functions 
become  more  complete.     The  function  of  motion,  the  instru- 
ments of  which  —  the   muscles   and  bones  —  have  been  con- 
sidered in  former  chapters,  and  all  the  other  animal  functions 
of  man,  depend  upon  the  set  of  organs  known  as  the  nervous 
system. 

4.  The  Nervous  System.  —  The  intimate  structure  of  this 
system  differs  from  any  tissue  which  we  have  before  examined. 
It  is  composed  of  a  soft,  pulpy  substance,  which  early  in  life  is 
almost  fluid,  but  which  gradually  solidifies  with  the  growth  of 
the  body.     When  examined  under  the  microscope,  it  is  found 
to  be  composed  of  two  distinct  elements :   (1)  the  white  sub- 
stance, composing  the  larger  proportion  of  the  nervous  organs 
of  the  body,  which  is  formed  of  delicate  cylindrical  filaments, 


2.  What  secor  d  set  of  powers  has  the  animal  ?    What  functions  are  mentioned  ?    The 
advantage  they  give  ? 

3.  Animals  whose  structure  is  simple  ?    As  we  approach  man  ?    Dependence  of  the 
animal  functions  of  man  ? 

4.  The  nervous  tissues,  of  what  composed  ?    When  examined  by  the  aid  of  the  micro- 
scope ?    The  white  substance  ?    The  gray  substance  ? 


THE  NERVOUS  SYSTEM  219 

about  -g-^Tj-  of  an  inch  in  diameter,  termed  the  nerve-fibres ; 
and  (2)  the  gray  substance,  composed  of  grayish-red,  or  ashen- 
colored  cells,  of  various  sizes,  generally  possessing  one  or  more 
off-shoots,  which  are  continuous  with  the  nerve-fibres  just  men- 
tioned. 

5.  Each  nerve-fibre  is  continuous  from  the  nerve-centre  from 
which  it  springs  to  that  part  of  the  body  in  which  it  ends. 
It  consists  of  a  white  sheath  and  a  gray  axis  cylinder  within. 
The  axis  cylinder  serves  to  convey  the  nerve-impulse,  while 
the  white  sheath  seems  to  serve  as  a  protection,  very  similar 
to  the  insulation  on  electric  wires.     Many  nerve-fibres  unite 
into  a  bundle  and  form  nerves.     These  nerve-bundles  may  be 
compared  to  electric  cables  containing  many  separate  wires. 
The  function  of  nerve-fibres  is  to  convey  nerve-impulses  from 
the  organs  and  periphery  of  the  body  to  the  nerve-centres,  or 
from  the  nerve-centres  to  the  organs  and  the  periphery. 

6.  The  gray,  cellular  substance  constitutes  the  larger  por- 
tion of  those  important  masses  which  bear  the  name  of  nervous 
centres  and  ganglia  (from  ganglion,  a  knot),  in  which  all  the 
nerve-fibres   unite.      The   function   of   nerve-centres  is  three- 
fold:" to   receive   nerve-impulses;     to   originate   and   impart 
nerve-impulses ;     and   to   transmit    nerve-impulses    from    one 
centre  to  another.      That  part  of  the  nervous  system  which 
is  concerned  in  the  animal  functions  comprises  the  brain,  the 
spinal   cord,  and   the    nerves  which   are   derived   therefrom; 
these  are,  together,  called  the  cerebro-spinal  system  (Fig.  54) ; 
while  that  other  set  of  organs,  which  presides  over  and  regu- 
lates the  vegetative  functions,  is  called  the  sympathetic  system 
of  nerves. 

7.  The  Brain.  —  The  brain  is  the  great  volume  of  nervous 
tissue  that  is  lodged  within  the  skull.     It  is  the  largest  and 
most  complex  of  the  nervous  centres ;  its  weight,  in  the  adult, 

5.  Of  what  does  a  nerve-fibre  consist?    Purpose  of  the  axis  cylinder?    Of  the  white 
sheath  ?     What  is  the  function  of  nerve-fibres  ? 

6.  Nervous  centres  and  ganglia?     Nerves?     What  do  they  serve?     Cerebro-spinal 
system  ? 

7.  Location  of  the  brain  ?     Its  weight?     Itsflhkpe?     Of  what  does  it  consist?     What 
organs  at  the  base  ?      x 


220 


THE  NERVOUS  SYSTEM 


FIG.  64.  — THE  CEBEBRO-SPINAL  SYSTEM 


THE  NERVOUS  SYSTEM  221 

being  about  fifty  ounces,  or  one-fortieth  of  that  of  the  whole 
body.  The  shape  of  the  brain  is  oval,  or  egg-shaped,-  with  one 
extremity  larger  than  the  other,  which  is  placed  posteriorly  in 
the  skull,  to  the  concavity  of  which  it  very  closely  conforms. 
The  brain  consists  chiefly  of  two  parts ;  the  cerebrum,  or  brain 
proper,  and  the  cerebellum,  or  "little  brain."  In  addition  to 
these,  there  are  several  smaller  organs  at  the  base,  among 
which  is  the  commencement  or  expansion  of  the  spinal  cord, 
termed  the  medulla  oblongata,  or  oblong  marrow. 

8.  The  tissue  of  the  brain  is  soft  and  easily  altered  in  shape 
by  pressure;  it  therefore  requires  to  be  placed  in  a  well-pro- 
tected position,  such  as  is  afforded  by  the  skull,  or  cranium, 
which  is  strong  without  being  cumbrous.      In  the  course  of 
an  ordinary  lifetime,  this  bony  box  sustains  many  blows  with 
little  inconvenience ;  while,  if  they  fell  directly  upon  the  brain, 
they  would  at  once,  and  completely,  disorganize  that  structure. 
Within  the  skull,  the  brain  is  enveloped  by  certain  membranes, 
which  at  once  protect  it  from  friction  and  furnish  it  with  a 
supply  of  nutrient  vessels;  they  are  called  the  arachnoid,  or 
"spider's  web,"  the   dura  mater,  and  the  pia  mater,  or  the 
"tough"  and  "delicate  coverings."     These   membranes   also 
cover  the  spinal  cord. 

9.  The  dura  mater  is  the  outer  covering.     It  is  very  strong 
and  tough,  being  composed  of  white  fibrous  and  elastic  tissue. 
Next  comes  the  arachnoid,  which  consists  of  two  layers  of  flat 
cells,  one  next  the  dura  mater,  and  the  other  next  the  pia 
mater.     Between  these  two  layers  is  contained  a  small  quan- 
tity of  watery  cerebro-spinal  fluid.     This  fluid  is  also  found  on 
the  pia  mater  in  the  folds  of  the  brain  surface.    The  pia  mater 
adheres  closely  to  the  surface  of  the  brain  and  spinal  cord.     It 
is  less  tough  and  less  closely  woven  with  fibrous  and  elastic 
tissue  than  the  dura  mater.     It  contains  a  network  of  blood- 
vessels which  nourish  the  brain.     The  supply  of  blood  sent  to 
the  brain  is  very  liberal,  amounting  to  one-fifth  of  all  that  the 

8.  The  tissu*  ef  the  brain  ?    What,  therefore,  is  required  ?    Blows  on  the  head  ?    Mem- 
branes of  th«  brain  ?    Blood  sent  to  the  brain  ? 

9.  The 4ura mater?    Arachnoid?    Cerebro-spinal  fluid  ?    The  pia  mater? 


222 


THE  KXltVOUS  SYSTEM 


entire  body  possesses.     The  brain  of  man  is  heavier  than  that 
of  any  other  animal,  except  the  elephant  and  whale. 

10.  The  Cerebrum. — The  brain  proper,  or  cerebrum,  is  the 
largest  of  the  intracranial  organs,  and  occupies  the  entire  upper 
and  front  portion  of  the  skull.  It  is  almost  completely  bisected 
by  a  fissure,  or  cleft,  running  through  it  lengthwise,  into  two 
equal  parts  called  hemispheres.  The  exterior  of  these  hemi- 


FIG.  55.— UPPER  SURFACE  OF  THE  CEREBRTTM 
A,  Longitudinal  Fissure  B,  The  Hemispheres 

spheres  is  gray  in  color,  consisting  chiefly  of  nerve-cells,  arranged 
so  as  to  form  a  layer  of  gray  matter  one-fifth  of  an  inch  in 
thickness,  and  is  abundantly  supplied  with  blood-vessels.  The 
interior  of  the  brain,  however,  is  composed  almost  wholly  of 
white  substance,  or  nerve-fibres. 

11.    The  surface  of  the  cerebrum  is  divided  by  a  considerable 
number  of  winding  and  irregular  furrows,  about  an  inch  deep, 


10.  'Where  is  the  cerebrum  located  ? 
hemispheres.    The  interior. 


How  is  it  divided  ?    Describe  the  exterior  of  the 


THE  NERVOUS  SYSTEM  223 

into  "  convolutions,"  as  shown  in  Fig.  55.  Into  these  furrows 
the  gray  matter  of  the  surface  is  extended,  and,  in  this  manner, 
its  quantity  is  vastly  increased.  The  extent  of  the  entire  sur- 
face of  the  brain,  with  the  convolutions  unfolded,  is  computed  to 
be  equal  to  four  square  feet ;  and  yet  it  is  easily  enclosed  within 
the  narrow  limits  of  the  skull.  When  it  is  stated  that  the 
gray  matter  is  the  true  source  of  nervous  power,  it  becomes 
evident  that  this  arrangement  has  an  important  bearing  on  the 
mental  capacity  of  the  individual.  And  it  is  noticed  that  in 
children,  before  the  mind  is  brought  into  vigorous  use,  these 


Fro.  56.  —  VERTICAL  SECTION  OF  THE  BRAIN 

A,  Left  Hemisphere  of  Cerebrum  D,  The  Pons  Varolii 

B,  Corpus  Callosum  E.  Upper  extremity  of  the  Spinal  Cord 

C,  Optic  Thalarnus  F,  The  Arbor  Vitse 


markings  or  furrows  on  the  surface  are  comparatively  shallow 
and  indistinct;  the  same  fact  is  true  of  the  brain  in  the  less 
civilized  races  of  mankind  and  in  the  lower  animals.  It  is  also 
noticeable  that  among  animals,  those  are  the  most  capable 

11.   The  surface  of  the  cerebrum,  how  marked  ?    The  gray  matter  of  the  surface?    Ex- 
tent of  the  entire  brain  surface  ?    Source  of  nervous  power  ?    What  farther  ? 


224  THE  NERVOUS  SYSTEM 

of  being  educated  which  have  the  best  development  of  the 
cerebrum.     (Head  Note  1.) 

12.   The  Cerebellum.  —  The  "little  brain"  is  placed  beneath 
the  posterior  part  of  the  cerebrum,  and,  like  the  latter,  is 


FIG.  57. —  LOWER  SURFACE  OF  T»E  BRAIN 
The  numbers  refer  to  the  pairs  of  nerves 

divided  into  hemispheres.     Like  it,  also,  the  surface  of  the 
cerebellum  is  composed  of  gray  matter,  and  its  interior  is 

1.  The  Brain.  —  "  Our  brains  are  seventy-year  clocks.  The  Aqgel  of 
Life  winds  them  up  once  for  all,  then  closes;the  case,  and  gives  tlie  key 
to  the  Angel  of  the  Resurrection.  Tic-tac  !  tic-tac  !  go  the  wheels  of 
thought ;  our  will  cannot  stop  them  ;  they  cannot  stop  themselves ;  sleep 
cannot  stop  them  ;  madness  only  makes  them  go  faster  ;  death  alone  can 
break  into  the  case,  and,  seizing  the  ever-swinging  pendulum,  which  we 
call  the  heart,  silence  at  last  the  clicking  of  the  terrible  escapement  we 
have  carried  so  long  beneath  our  wrinkled  foreheads.  .  .  .  Now,  when 
a  gentleman's  brain  is  ill-regulated  or  empty,  it  is,  to  a  great  extent,  his 
own  fault,  and  so  it  is  simple  retribution  that,  while  he  lies  slothfully  or 
aimlessly  dreaming,  the  fatal  habit  settles  on  him  like  a  vampire  and 
sucks  his  blood,  fanning  him  all  the  while  with  its  hot  wings  into  deeper 
slumber  or  idler  dreams."  —  Holmes'  The  Autocrat  of  the  Breakfast-  Table. 

12.  Location  of  the  "  little  brain  ?  "  How  divided  ?  Its  surface  and  interior  ?  Its  sub- 
divisions ?  Its  size  ? 


THE  NERVOUS  SYSTEM  225 

chiefly  white  matter.  It  has,  however,  no  convolutions,  but  is 
subdivided  by  many  parallel  ridges,  which,  sending  down  gray 
matter  deeply  into  the  white,  central  portion,  give  the  latter 
a  somewhat  branched  appearance..  This  peculiar  appearance 
has  been  called  the  arbor  vitce.,  or  the  "  tree  of  life,"  from  the 
fact  that  when  a  section  of  the  organ  is  made,  it  bears  some 
resemblance  to  the  trunk  and  branches  of  a  tree  (Fig.  56,  F). 
In  size,  this  cerebellum,  or  "little  brain,"  is  less  than  one- 
eighth  of  the  cerebrum. 

13.  From  the  under  surface  of  the  cerebrum,  and  from  the 
front  margin  of  the  cerebellum,  fibres  collect  together  to  form 
the  medulla  oblongata  (Fig.  57,  Ma),  which,  on  issuing  from 
the  skull,  enters  the  spinal  column,  and  then  becomes  known 
as  the  spinal  chord.     From  the  base  of  the  brain,  and  from  the 
sides  of  the  medulla  originate,  also,  the  cranial  nerves,  of  which 
there   are   twelve  pairs.     These   nerves   are   round   cords   of 
glistening  white  appearance,  and,  like  the  arteries,  generally 
lie  remote  from  the  surface  of  the  body  and  are  well  protected 
from  injury. 

14.  THE  CRANIAL  NERVES 

First  Pair.     The  Olfactory  Nerves 

They  pass  from  the  base  of  the  brain  to  the  horizontal  plate 
of  the  ethmoid  bone,  and  send  numerous  filaments  through  its 
many  perforations  into  the  mucous  membranes  of  the  nose. 
They  convey  the  sense  of  smell. 

Second  Pair.     The  Optic  Nerves 

They  convey  the  sense  of  sight,  and  control  the  contractile 
movements  of  the  iris. 

Tliird  Pair.     The  Oculomotorius  ** 

It  supplies  most  of  the  muscles  moving  the  eyeball. 

18.   Of  what  is  the  medulla  oblongata  formed  ? 
Of  what  does  it  form  a  part  ? 
Source  of  the  cranial  nerves  ?    How  many  ? 
Appearance  of  the  cranial  nerves  ?    Location  ? 


226  THE  NERVOUS  SYSTEM 

Fourth  Pair.     The  Patheticus 

Its  only  function  is  to  control  the  action  of  the  superior 
oblique  muscle  of  the  eye. 

Fifth  Pair.     TJie  Trigeminus 

This  is  the  great  sensitive  nerve  of  the  face,  supplying  the 
skin  and  mucous  membrane  of  this  region.  It  also  has  motor 
fibres  which  control  certain  muscles  of  the  face.  It  also  sup- 
plies certain  parts  of  the  eye,  nose,  and  lachrymal  glands,  the 
teeth  in  both  the  upper  and  lower  jaws,  the  salivary  glands, 
and  the  tongue. 

Sixth  Pair.     The  Abducens 

It  is  exclusively  a  motor  nerve,  controlling  only  one  muscle, 
namely,  the  external  straight  muscle  of  the  eyeball. 

Seventh  Pair.     Tlie  Facial  Nerves 

They  are  the  motor  nerves  for  the  superficial  muscles  of  the 
face,  and  may  be  correctly  called  the  nerves  of  expression,  by 
which  the  features  are  animated  in  their  varying  movements, 
corresponding  with  the  different  phases  of  mental  or  emotional 
activity. 

Eighth  Pair.     TJie  Auditory  Nerves 

They  are  distributed  to  the  internal  ear  only,  and  form  the 
only  connection  between  this  and  the  brain,  transmitting  the 
nerve  .impulses  which  produce  the  sensation  of  sound. 

Ninth  Pair.     TJie  Glossopharyngeal  Nerves 

They  are  both  sensitive  and  motor  nerves,  controlling  the 
sense  of  taste  and  the  act  of  deglutition. 

14.   What  is  stated  of  the  olfactory  nerves  ?    The  optic  nerves  ? 
The  oculomotorius  ?    The  patheticus  ?    The  trigeminus  ? 
The  abducens  ?    The  facial  nerves  ?    The  auditory  nerves  ? 
The  gloasopharyngeal  ? 


THE  NERVOUS  SYSTEM  227 

Tenth  Pair.     The  Pneumogastric  Nerves 

They  are  the  longest  and  most  widely  distributed  of  all  the 
cranial  nerves.  It  goes  to  the  pharynx,  oasophagus,  stomach, 
liver,  intestines ;  to  the  larynx,  trachea,  lungs,  and  heart. 

Eleventh  Pair.     The  Spinal  Accessory  Nerves 

As  its  name  implies,  this  nerve  received  a  part  of  its  origin 
from  the  spinal  cord,  in  the  cervical  region.  A  portion  of  it 
is  incorporated  in  the  vagus,  and  the  other  part  supplies  cer- 
tain muscles  of  the  neck  and  chest.  Some  of  its  fibres  entirely 
control  the  power  of  the  vocal  chords  to  produce  sounds. 

Twelfth  Pair.     The  Hypoglossal  Nerves 
Its  only  function  is  the  control  of  the  motions  of  the  tongue. 

15.  The  Spinal  Cord.  —  The  spinal  cord,  or  "  marrow,"  is  a 
cylindrical   mass   of    soft  nervous   tissue,   which  occupies  a 
chamber,  or  tunnel,  fashioned   for  it  in  the  spinal   column 
(Figs.  58  and  59).     It  is  composed    of  the  same  substances 
as  the  brain;  but  the  arrangement  is  exactly  reversed  —  the 
white  matter  encompassing  or  surrounding  the  gray  matter, 
instead  of  being  encompassed  by  it.     The  amount  of  the  white 
substance  is  also  greatly  in  excess  of  the  other  material.     A 
vertical  fissure  partly  separates  the  cord  into  two  lateral  halves, 
and  each  half  is  composed  of  two  separate  bundles  of  fibres, 
which  are  named  the  anterior  and  posterior  columns. 

16.  These  columns  have  entirely  different  uses,  and  each  of 
them  unites  with  a  different  portion  of  the  nerves  which  have 
their  origin  in  the  spinal  cord.     The  importance  of  this  part 
of  the  nervous  system  is  apparent  from  the  extreme  care  taken 

What  is  stated  of  the  pneumogastric  nerves  ?  The  spinal  accessory  nerves  ?  The 
hypoglossal  nerves  ? 

15.  Describe  the  composition  of  the  spinal  cord.     What  space  does  the  spinal  cord  'oc- 
cupy ?    In  what  respect  does  the  substance  composing  the  spinal  cord  and  the  substance 
composing  the  brain  agree  ?    In  what  respect  do  they  differ?    Does  white  or  gray  matter 
predominate  in  the  spinal  cord  ?    In  the  brain  ?    How  is  the  spinal  cord  divided  ?    Compo- 
sition of  each  half  ?    Names  ? 

16.  Uses  of  these  columns  ?    Importance  of  this  part  of  the  nervous  system  ?    How 
protected  ?    The  three  membranes  that  cover  the  brain  ?  _ 


228 


THE  NERVOUS  SYSTEM 


to  protect  it  from  external  injury.  For,  while  a  very  slight 
disturbance  of  its  structure  suffices  to  disarm  it  of  its  power, 
yet  so  staunch  is  its  bony  enclos- 
ure, that  only  by  very  severe  inju- 
ries is  it  put  in  peril.  The  three 
membranes  that  cover  the  brain  are 
continued  downward,  so  as  to  en- 
velope and  still  further  shield  this 
delicate  organism. 

17.  The    Spinal    Nerves. — The 
spinal  nerves,   thirty-one   pairs  in 
number,  spring  from  each  side  of 
the  cord  by  two  roots,  an  anterior 
and  a  posterior  root,  which  have  the 
same  functions  as  the  columns  bear- 
ing similar  names.      The  posterior 
root  is  distinguished  by  possessing 
a  ganglion  of  gray  matter,  and  by  a 
somewhat  larger  size.    The  succes- 
sive points  of  departure,  or  the  off- 
shooting  of  these  nerves,  occur  at 
short  and  nearly  regular  intervals 
along  the  course  of  the  spinal  cord. 
Soon  after  leaving  these  points,  the 
anterior  and  posterior  roots  unite  to 
form  the  trunk  of  a  nerve,  which  is 
distributed,  by  means  of  branches, 
to  the  various  organs  of  that  part 
of  the  body  which  this   nerve   is 
designed   to   serve.     The    spinal 
nerves  supply  chiefly  the  muscles 
of  the   trunk   and  limbs   and  the 
external  surface  of  the  body. 

18.  The    tissue    composing   the 
nerves    is    entirely    of    the    white 


FIG.  58 


A,  CEREBRUM,  B,  CEREBELLUM, 
D,  D,  SPINAL  CORD 


17.  The  spinal  nerves  ?    The  posterior  root  ?   The  nerves,  how  arranged  ?    Their  office? 

18.  The  nerve  tissue  ~t    Its  oliui-acter  ?    Course  of  each  nerve-fibre  ? 


77/A'  XERVOUS  SYSTEM  229 

variety,  or,  in  other  words,  the  nerve-fibres ;  the  same  as  we 
have  observed  forming  a  part  of  the  brain.  But  the  nerves, 
instead  of  being  soft  and  pulpy,  as  in  the  case  of  the  brain, 
are  dense  in  structure,  being  hardened  and  strengthened  by 
means  of  a  fibrous  tissue  which  surrounds  each  of  these  deli- 
cate fibres,  and  binds  them  together  in  glistening,  silvery 
bundles.  Delicate  and  minutely  fine  as  are  these  nerve-fibres, 


FIG.  54>.  —  SECTION  OF  SPINAL  CORD,  WITH  ROOTS  OF  SPINAL  NERVES.    FRONT  VIEW 

it  is  probable  that  each  of  them  pursues  an  unbroken,  isolated 
course,  from  its  origin,  in  the  brain  or  elsewhere,  to  that  par- 
ticular point  which  it  is  intended  to  serve.  For,  although  their 
extremities  are  often  only  a  hair's  breadth  distant  from  each 
other,  the  impression  which  any  one  of  them  communicates  is 
perfectly  distinct,  and  is  referred  to  the  exact  point  whence 
it  came. 

19.  This  may  be  illustrated  in  a  simple  manner,  thus :  if  two 
fingers  be  pressed  closely  together,  and  the  point  of  a  pin  be 
carried  lightly  across  from  one  to  the  other,  the  eyes  may  be 
closed,  and  yet  we  can  easily  note  the  precise  instant  when 
the  pin  passes  from  one  finger  to  the  other.  If  the  nerve- 
fibres  were  less  independent,  and  if  it  were  necessary  that  they 
should  blend  with  and  support  each  other,  all  accuracy  of 
perception  would  be  lost,  and  all  information  thus  afforded 
would  be  pointless  and  confused.  These  silvery  threads  must, 
therefore,  be  spun  out  with  an  infinite  degree  of  nicety.  Imag- 
ine, for  instance,  the  fibre  which  connects  the  brain  with  some 

19.  How  may  we  illustrate  the  fact  ?  The  fibre  connecting  the  brain  with  a  point  in  the 
foot? 


230  THE  NERVOUS  SYSTEM 

point  on  the  foot  —  its  length  cannot  be  less  than  one  hundred 
thousand  times  greater  than  its  diameter,  and  yet  it  performs 
its  work  with  as  much  precision  as  fibres  that  are  compara- 
tively much  stronger,  and  less  exposed.  (Head  Note  2.) 

20.  The  Sympathetic  System.  — •  The  sympathetic  system  of 
nerves  remains  to  be  described.  It  consists  of  a  double  chain 
of  ganglia,  situated  on  each  side  of  the  spinal  column,  and 
extending  through  the  cavities  of  the  trunk,  and  along  the 
neck  into  the  head.  These  ganglia  are  made  up  for  the  most 
part  of  small  collections  of  gray  nerve-cells,  and  are  the  nerve- 
centres  of  this  system.  Prom  these,  numerous  small  nerves 
are  derived,  which  connect  the  ganglia  together,  send  out 
branches  to  the  cranial  and  spinal  nerves,  and  form  networks 
in  the  vicinity  of  the  stomach  and  other  large  organs.  A  con- 
siderable portion  of  them  also  follows  the  distribution  of  the 
large  and  small  ,  blood-vessels,  in  which  the  muscular  tunic 
appears.  Branches  also  ascend  into  the  head,  and  supply  the 
muscles  of  the  eye  and  ear,  and  other  organs  of  sense. 

2.  How  Bodily  Sensations  are  Located.  —  "A  nervous  fibre  which  ends 
in  the  skin  forms,  as  far  as  its  union  with  the  brain  or  cord  is  concerned, 
one  long,  fine,  unbroken  thread.  The  fibres,  thus  ending  in  the  skin, 
very  soon  join  to  form  small  branches,  and  finally  in  thick  nerve  trunks, 
but  in  no  case  do  two  nerve  fibres  coalesce  so  as  to  lose  their  identity. 
Every  part  of  the  skin  has  its  own  separate  connections  with  the  centre 
of  the  nervous  systems,  which  unite  there  just  as  telegraph  wires  unite 
at  a  terminus.  The  brain  is  the  terminus  of  these  lines  of  nerves,  and, 
as  it  were,  receives  and  explains  the  messages  sent  to  it.  It  distinguishes 
very  clearly  by  what  particular  fibre  such  a  message  has  come,  and  just 
as  the  clerk  in  a  telegraph  office,  where  a  great  many  wires  meet  from  all 
sides,  knows  by  experience  from  what  direction  each  wire  brings  its 
message,  so  the  brain  also  knows  by  experience  what  part  of  the  skin 
is  involved  when  a  sensation  reaches  it  along  a  certain  nerve  fibre.  It  is 
probable  that  the  brain,  by  its  imaginative  faculty,  has  formed  a  complete 
picture  of  the  surface  of  the  body  —  a  kind  of  chart  slowly  made,  and 
always  being  more  highly  perfected,  by  means  of  which,  with  each  im- 
pression from  without,  there  arises  in  the  brain  a  picture  of  the  spot  upon 
the  skin  where  the  irritation  has  taken  place.  Now,  if  an  irritation  were 
to  pass  from  one  nerve  fibre  to  another,  it  is  very  plain,  the  brain  could 
not  tell  the  place  from  which  it  came,  and  could  not  localize  impressions 
received  from  the  world  about  us."  —  Bernstein's  Five  Senses  of  Man. 


20.  The  sympathetic  system  of  nerves  ?    Of  what  does  it  consist  J 


THE  NERVOUS  SYSTEM  231 

21.  In  this   manner  the   various  regions  of  the  body  are 
associated  with  each  other  by  a  nervous  apparatus,  which  is 
only  indirectly  connected  with  the  brain  and  spinal  cord,  and 
thus  it  is  arranged  that  the  most  widely  separated  organs  of 
the  body  are  brought  into  close  and  active  sympathy  with  each 
other,  so  that  "  if  one  member  suffers,  all  the  other  members 
suffer  with  it."    From  this  fact,  the  name  sympathetic  system, 
or  the  great  sympathetic  nerve,  has  been  given  to  the  Compli- 
cated apparatus   we  have  briefly   described.     Blushing  and 
pallor  are  caused  by  mental  emotions,  as  modesty  and  fear, 
which  produce  opposite  conditions  of  the  capillaries  of  the 
face  by  means  of  these  sympathetic  nerves.     (Head  Note  3.) 

22.  The  Properties  of  Nervous  Tissue. — We  have  seen  that 
in  all  parts  of  this  system  there  are  only  two  forms  of  nervous 
tissue,  namely,  the  gray  substance  and  the  white  substance,  so 
called  from  their  difference  of  color  as  seen  by  the  naked  eye ; 

3.  The  Wonderful  Operations  of  the  Sympathetic  System.  —  Blush- 
ing or  "Shame-redness."  —  "  A  blow  upon  the  head  will  knock  a  man 
senseless,  but  he  still  lives  and  survives  ;  a  blow  of  like  violence  upon 
the  pit  of  the  stomach  is  followed  by  instant  death,  because  the  great 
centre  of  the  organic  nerves  lies  there,  and  the  vital  actions  are  suspended 
by  the  blow,  so  that  the  system  never  lives  to  recover,  but  abolition  of 
function  and  of  life  at  once  follows.  Other  actions  also  belong  >to  this 
organic  nervous  system.  It  controls  the  caliber  of  the  blood-vessels,  for 
which  end  filaments  run  along  each  of  them.  The  body  temperature  is 
maintained  by  the  production  and  dispersion  of  heat  thus  regulated,  a 
continuous  oscillation  going  on  betwixt  the  internal  vessels  and  those  of 
the  skin.  It  is  connected  with  the  emotions  ;  and  so  the  heart  beats  per- 
ceptibly with  excitement,  and  the  maiden's  cheek  blushes  before  words 
that  should  never  be  spoken,  or  thoughts  that  should  never  arise.  The 
momentary  dilatation  of.  the  vessels  of  the  skin  constitutes  the  blush  (in 
the  German,  *  shame-redness  *),  which  is  not  confined  to  the  face,  though 
of  course  it  is  only  seen  there  —  the  body  being  hid  by  the  clothes."  — 
Fothergill  on  the  Maintenance  of  Health. 

"There  is  an  old  tradition  that  when  the  executioner  of  Charlotte 
Corday  lifted  her  severed  head  high  in  air,  and  smote  the  face  with  his  hand, 
the  cheeks  were  seen  to  resent  the  insult  with  a  blush.  This  reddening  is 
not  impossible,  for  a  decapitated  head  certainly  may  exhibit,  for  a  time, 
certain  reflex  movements.  But  whether  sensibility  is  retained  cannot  be 
known."  

21.  Association  of  the  various  regions  of  the  body  ?    If  one  member  suffers  ?   Blushing  ? 

22.  Properties  of  nervous  tissue  ?    Office  of  the  gray  substance  ?  xOf  the  white  ?    The 
nervous  centres  ?    White  fibres  ? 


232  THE  NERVOUS  SYSTEM 

or  the  nerve-cell,  and  the  nerve-fibre,  so  called  from  their 
microscopic  appearance.  Now  these  two  tissues  are  not  com- 
monly mingled  together,  but  either  form  separate  organs  or 
distinct  parts  of  the  same  organs.  This  leads  us  to  the  con- 
clusion that  their  respective  uses  are  distinct.  And  this  proves 
to  be  the  simple  fact ;  wherever  we  find  the  gray  substance,  we 
must  look  upon  it  as  performing  an  active  part  in  the  system 
— that  is,  it  originates  nervous  impulses ;  the  white  matter,  on 
the  contrary,  is  a  passive  agent,  and  serves  merely  as  a  con- 
ductor of  nervous  influences.  Accordingly,  the  nervous  centres, 
composed  so  largely  of  the  gray  cells,  are  the  great  centres  of 
power,  and  the  white  fibres  are  simply  the  instruments  by 
which  the  former  communicate  with  the  near  and  distant 
regions  of  the  body  under  their  control. 

23.  We  may  compare  the  brain,  then,  to  the  capital,  or  seat 
of  government,  while  the  various  ganglia,  including  the  gray 
matter  of  the  cord,  like  so  many  subordinate  official  posts,  are 
invested  with  authority  over  the  outlying  provinces ;  and  the 
nerves,  with  the  white  matter  of  the  cord,  are  the  highways 
over  which  messages  go  and  return  between  these  provinces 
and  the  local  or  central  governments.  But  both  forms  of  ner- 
vous tissue  possess  the  same  vital  property  called  excitability, 
by  which  term  is  meant  that,  when  a  nerve-cell  or  fibre  is 
stimulated  by  some  external  agent,  it  is  capable  of  receiving 
an  impression,  and  of  being  by  it  excited  into  activity.  A  ray 
of  light,  for  example,  falling  upon  one  extremity  of  a  fibre  in 
the  eye',  excites  it  throughout  its  whole  length ;  and  its  other 
extremity  within  the  brain,  communicating  with  a  nerve-cell, 
the  latter  in  its  turn  is  excited,  and  the  sensation  of  sight  is 
produced.  (Read  Note  4.)' 

4.  The  Relations  of  the  Brain  and  Sympathetic  Nerve.  —  "  Buried  in 
the  hidden  recesses  of  the  body,  between  the  spinal  column  and  the  great 
organs  of  nutrition,  there  is  a  double  row  of  small  knots  of  nervous  sub- 
stance, bound  together  by  a  series  of  nerves  running  from  one  to  another, 
in  succession,  from  the  neck  to  the  base  of  the  column.  The  whole 
appears  like  a  long,  fine  cord,  with  knots  at  various  distances  —  a  collec- 


28.    What  comparison  is  made  between  the  brain  and  the  nation's  capital  ?    The  vital 
property,  excitability  ?    What  example  is  given  ? 


THE  NERVOUS  SYSTEM  233 

24.  What  sort  of  change  takes  place  in  the  nervous  tissue 
when  its  excitability  is  aroused,  is  not  known ;  certainly  none 
is  visible.     On  this  account,  it  has  been  thought  by  some  that 
the  nerve-fibre  acts  after  the  manner  of  a  telegraph  wire ;  that 
is,  it  transmits  its  messages  without  undergoing  any  material 
change  of  form.     But  though  the  comparison  is  a  convenient 
one,  it  is  far  from  being  strictly  applicable,  and  the  notion 
that  nerve-force  is  identical  with  electricity  has  been  fully 
proved  to  be  incorrect. 

25.  The  Functions  of  the  Nerves.  —  The  nerves  are  the  in| 
strum ents  of  the  two  grand  functions  of  the  nervous  system— f 
Sensation  and  Motion.    They  are  not  the  true  centres  of  eithef 
function,  but  they  are  the  conductors  of  influences  which  occaj- 
sion  both.     If  the  nerve  in  a  limb  of  a  living  animal  be  laid 
bare,  and  irritated  by  pinching,  galvanizing,  or  the  like,  two 
results  follow,  namely:   the  animal  experiences  a  sensation, 
that  of  pain,  in  the  part  in  which  the  nerve  is  distributed,  and 
the  limb  is  thrown  into  convulsive  action.     When  a  nerve  in  a 
human  body  is  cut  by  accident,  or  destroyed  by  disease,  the 
part  in  which  it  ramifies  loses  both  sensation  and  power  of 
motion;  or,  in  other  words,  it  is  paralyzed.     We  accordingly 
say  that  the  nerves  have  a  two-fold  use  —  a  sensory  and  a 
motor  function. 

tion  of  little  brains,  if  I  may  use  a  rather  crude  expression.  It  is,  as  the 
Swiss  would  say,  the  'great  council'  of  this  federative  republic,  which 
counterpoises  that  cerebral  royalty  within  us.  It  has  been  well  name'd 
the  great  sympathetic  nerve,  and  this  it  is  which  makes  the  laws  by 
which  our  interior  life  is  governed.  The  nutritive  apparatus  of  a  country, 
its  commerce,  its  industry,  the  incessant  labor  of  its  citizens,  by  which 
the  public  wealth  is  built  up  —  and  also  let  us  add,  the  throbs  of  the 
national  heart  —  all  this  the  sympathetic  system  full  plainly  shows  us 
should  be  left  to  itself.  It  would  be  a  fine  affair  if  the  brain  had  to 
watch  over  the  service  of  the  stomach,  or  if,  at  its  convenience,  it  regu- 
lated the  movements  of  the  master  who  disposes  of  its  life.  Besides,' 
what  would  become  of  the  poor  body  if  the  least  drowsiness  attacked  the 
universal  centre  ?  Happy  it  is  for  us  —  and  let  us  not  be  slow  to  own  it  — 
that  nature  has  armed  herself  against  these  encroachments  of  power."  — 
Mace's  The  Little  Kingdom. 


24.  Change  in  the  nervous  tissues  ?    Nerve  force  and  electricity  ? 

25.  Functions  of  the  nerves  ?    In  the  case  of  the  aerve  of  a  living  animal  ?    Of  the 
human  body  ? 


234  THE  NERVOUS  SYSTEM 

26.  If  a  nerve  that  has  been  exposed  be  divided,  and  the 
inner  end,  or  that  still  in  connection  with  the  nerve-centres  be 
irritated,  sensation  is  produced,  but  no  movement  takes  place. 
But  if  the  outer  end, 
or  that  still  connected 
with  the  limb,  be  irri- 
tated, then  no  pain  is 

felt,  but  muscular  con-  ^|liJ|8P§^         f]/*^  «/ 
tractions  are  produced. 
Thus    we    prove    that 

r  <  FIG.  60.  —  ILLUSTRATING  THE  FUNCTIONS  OF  THE 

there  are  two  distinct  SPINAL  NERVES 


Sets     Of    fibres     in    the      DtvMed  at  a.  —  Irritated  at  1  :  pain.    Irritated  at  2  : 

muscular  contraction 

nerves  —  one  of  which, 

the  sensory  fibres,  conduct  toward  the  brain,  and  another,  the 
motor  fibres,  conduct  to  the  muscles  (see  Fig.  60).  The 
former  may  be  said  to  begin  in  the  skin  and  other  organs 
and  end  in  the  brain,  while  the  latter  begin  in  the  nervous 
centres  and  end  in  the  muscles.  They  are  like  a  double  line 
of  telegraph  wires,  one  for  inquiries,  the  other  for  responses. 

27.  We  have  already  spoken  of  the  two  roots  of  the  spinal 
nerves,  called,  from  their  points  of  origin  in  the  spinal  cord, 
the  anterior  and  posterior  roots.     These  have  been  separately 
cut  and  irritated  in  the  living  animal,  and  it  has  been  found 
that  the  posterior  root  contains  only  sensory  fibres,  and  the 
anterior  root  has  only  motor  fibres.     So  that  the  nerves  of  a 
limb  may  be  injured  in  such  a  way  that  it  will  retain  power  of 
motion  and  yet  lose  sensation  ;  or  the  reverse  condition,  feeling 
without  motion,  may  exist.     Between  these  two  sorts  of  fibres 
no  difference  of  structure  can  be  found  ;  and  where  they  have 
joined  to  form  a  nerve,  it  is  impossible  to  distinguish  one  sort 
from  the  other. 

28.  Occasionally  a  nerve  is  so  compressed  as  to  be  tempo- 
rarily unable  to  perform  its  functions  :  a  transient  paralysis 

26.  If  an  exposed  nerve  be  divided  ?    What  is  proved  ?    The  course  of  the  sensory  set 
of  fibres  ?    Of  the  motor  set  ?    To  what  are  they  likened  ? 

27.  The  two  roots  of  the  spinal  nerves  ?    What  has  been  found  ?    Difference  of  the  two 
sorts  of  fibres  ?    Kesult  of  their  union  ? 

28.  Transient  paralysis  ?    When  such  is  the  case  with  the  leg  ?    What  other  fact  is 
observed  ? 


THE  NERVOUS  SYSTEM  235 

then  takes  place.  This  is  the  case  when  the  leg  or  arm  "  gets 
asleep,"  as  it  is  expressed.  When  such  is  the  condition  with 
the  leg,  and  the  person  suddenly  attempts  to  walk,  he  is  liable 
to  fall,  inasmuch  as  the  motor  fibres  cannot  convey  orders  to 
the  muscles  of  the  limb.  Another  fact  is  observed:  there  is 
no  sensation  in  this  nerve  at  the  point  of  its  compression ;  but 
the  whole  limb  is  numb,  and  tingling  sensations  are  felt  in  the 
foot  —  the  point  from  which  the  sensory  fibres  arise. 

29.  This  illustrates  the  manner  in  which  the  brain  inter- 
prets all  injuries  of  the  trunk  of  a  nerve.     Sensation  or  pain 
is  not  felt  at  the  point  of  injury,  but  is  referred  to  the  outer 
extremities   of  the  nerve,  where  impressions  are  habitually 
received.     This   is   the   reason  why,  after  a  limb  has  been 
amputated  by  the  surgeon,  the  patient  appears  to  suffer  pain 
in  the  member  that  has  been  severed  from  the  body;  while 
some  form  of  irritation  at  the  end  of  the  nerve  in  the  wound, 
or  stump,  is  the  real  source  of  his  distress.     Again,  when  the 
"funny-bone"  —  that  is,  the  ulnar  nerve  at  the   elbow  —  is 
accidentally  struck,  the  tingling  sensations  thus  produced  are 
referred  to  the  outer  side  of  the  hand  and  the  little  finger,  the 
parts  to  which  that  nerve  is  distributed. 

30.  All  the  spinal  nerves,  and  two  from  the  brain,  are  con- 
cerned in  both  sensation  and  motion.     Of  the  remainder  of 
the  cranial  nerves,  some  are  exclusively  motor,  others  exclu- 
sively sensory;  and  still  others  convey,  not  ordinary  sensa- 
tions, but  special  impressions,  such  as   sight,  hearing,  and 
smell,  which  we  have  yet  to  consider.     However  much  the 
functions  of  the  nerves  seem  to  vary,  there  is  but  little  dif- 
ference discoverable  in  the  nerves  themselves,  when  examined 
under  the  microscope.     Whatever  difference  exists  must  be 
accounted  for  in  consequence  of  the  nerves  communicating 
with  different  portions  of  the  gray  matter  of  the  brain.     The 
rate  of  motion  of  a  message,  to  or  from  the  brain  along  a 

29.  What  does  this  illustrate  ?  Sensation  ?  The  feeling  after  a  limb  has  been  ampu- 
tated ?  Striking  of  the  "  funny-bone  ?  " 

80.  The  spinal  nerves,  and  two  from  the  brain  ?  Of  the  remainder  ?  Difference  in  the 
nerves  ?  How  accounted  for  ?  The  rate  of  conduction  along  a  nerve  f  As  compared  with 
electricity  ? 


236  THE  NERVOUS  SYSTEM 

nerve,  has  been  measured  by  experiment  upon  the  lower  ani- 
mals, and  estimated  in  the  case  of  man  at  about  two  hundred 
feet  per  second.  As  compared  with  that  of  electricity,  this  is 
a  very  slow  rate,  but,  in  respect  to  the  size  of  the  human, 
body,  it  is  practically  instantaneous.  (Eead  Note  5.) 

31.  The  Functions  of  the  Spinal  Cord.  — As  the  anterior  and 
posterior  roots  of  the  spinal  nerves  have  separate  functions,  so 
the  anterior  and  posterior  columns  of  'the  cord  are  distinct 
in  function.     The  former  are  concerned  in  the  production  of 
motion,  the  latter  in  sensation.     If  the  cord  be  divided,  as 
before  in  the  case  of  the  nerve,  it  is  found  that  the  parts 
below  the  point  of  injury  are  deprived  of  sensation  and  of 
the  power  of  voluntary  motion  on  both  sides  of  the  body  —  a 
form  of  paralysis  which  is  called  paraplegia. 

32.  This  form  of  disease  —  paraplegia  —  is  sometimes  seen 
among  men,  generally  as  the  result  of  a  fall,  or  some  other 
severe  accident,  by  which  the  bones  of  the  spine  are  broken, 
and  the  cord  is  crushed,  or  pierced  by  fragments  of  bone. 
The  parts  which  are  supplied  by  nerves  from  the  cord  above 
the  point  of  injury  are  as  sensitive  and  mobile  as  before.     The 
results  are  similar,  whether  the  division  happens  at  a  higher 
or   lower   portion   of   the    spinal    cord;    but    the    danger   to 
life  increases   proportionately  as   the   injury  approaches  the 
brain.     When  it  occurs  in  the  neck,  the  muscles  of  inspira- 


5.  The  Speed  of  Sensation  and  Thought.  —  "The  rate  of  nervous 
and  mental  action  is  not  the  same  in  all  individuals.  In  comparing  the 
records  made  by  astronomers,  it  has  been  found  that  an  appreciable  dif- 
ference exists  in  the  rapidity  with  which  the  same  occurrence  may  be 
noted  by  different  observers.  This  is  known  as  the  'personal  equation,' 
and  is  allowed  for  with  the  greatest  nicety  in  the  making  up  of  astro- 
nomical reports.  With  very  delicate  apparatus  for  marking  time,  the 
various  nervous  itnpulses  have  been  observed;  from  forty  to  a  hun- 
dred feet  in  a  second  are  the  estimates  of  different  experiments  as  to  the 
speed  of  sensation  ;  or,  as  it  has  been  expressed,  it  would  take  a  full- 
grown  whale  a  second  to  feel  the  stroke  of  a  harpoon  in  his  tail." 


31.  Functions  of  the  anterior  and  posterior  columns  of  the  cord  ?    If  the  cord  be 
divided  ? 

32.  Paraplegia  ?    Kesult  and  danger  to  life  ?    When  the  injury  occurs  in  the  neck  ? 


THE  NERVOUS  SYSTEM  237 

tion  are  paralyzed,  since  they  are  supplied  by  nerves  issu- 
ing from  that  region;  and  as  a  result  of  this  paralysis, 
the  lungs  are  unable  to  act,  and  life  is  speedily  brought  to 
a  close. 

33.  When  the  spinal  cord  of  an  animal  has  been  cut,  in 
experiment,  it  may  be  irritated  in  a  manner  similar  to  that 
alluded  to  when  considering  the  nerves.    If,  then,  the  upper  cut 
surface  be  excited,  it  is  found  that  pain,  referable  to  the  parts 
below  the  cut,  is  produced ;  but  when  the  lower  cut  surface  is 
irritated,  no  feeling  is  manifested.     So  we  conclude  that  in 
respect  to  sensation,  the  spinal  cord  is  not  its  true  centre,  but 
that  it  is  merely  a  conductor,  and  is  therefore  the  great  sensory 
nerve  of  the  body.     When  the  lower  surface  of  the  cut  is  irri- 
tated, the  muscles  of  the  parts  below  the  section  are  violently 
contracted.     Hence  we  conclude  that,  in  respect  to  the  move- 
ments ordered  by  the  will,  the  spinal  cord  is  not  their  source, 
but  that  it  acts  only  as  a  conductor,  and  is,  accordingly,  the 
great  motor  nerve  of  the  body. 

34.  Direction  of  the  Fibres  of  the  Cord.  —If  one  lateral  half 
of  the  spinal  cord  be  cut,  or  injured,  a  very  singular  fact  is 
observed.     All  voluntary  power  over  the  muscles  of  the  corre- 
sponding half  of  the  body  is  lost,  but  the  sensibility  of  that 
side  lemains  undiminished.     This  result  shows  that  the  motor 
fibres  of  the  cord  pursue  a  direct  course,  while  its   sensory 
fibres  are  bent  from  their  course.    And  this  has  been  proved  to 
be  the  fact;   for  immediately  after  the  posterior  roots  —  the 
conductors  of  sensory  impressions — join  the  posterior  columns, 
they   enter  the   gray  matter  of  the  cord,  and  passing  over, 
ascend  to  the  brain  on  the  opposite  side.      Accordingly,  the 
sensory  fibres  from  the  right  and  left  sides  interlace  each  other 
in  the  gray  matter;   this  arrangement  has  been  termed  the 
decussation,  or  crossing  of  these  fibres.     This  condition  serves 
to  explain  how  a  disease  or  injury  of  the  cord  may  cause  a 
paralysis  of  motion  in  one  leg,  and  a  loss  of  sensation  in  the 
other. 


83.  Experiment  of  cutting  the  spinal  cord  of  an  animal  ?    What  inference  is  drawn  ? 

84.  What  singular  fact  is  noticed  ?     What  does  the  result  show  ' 


238  THE  NERVOUS  SYSTEM 

35.  The  direction  of  the  anterior,  or  motor  columns  of  the 
cord,  is  downward  from  the   brain.     In   the   cord   itself,  the 
course  of  the  motor  fibres  is  for  the  most  part  a  direct  one ; 
but  in  the  medulla  oblongata,  or  upper  extremity  of  the  cord, 
and  therefore  early  in  their  career,  these  fibres  cross  from  side 
to  side  in  a  mass,  and  not  separately,  as  in  the  case  of  the 
posterior  fibres  just  mentioned.     This  arrangement  is  termed 
the  decussation  of  the  anterior  columns  of  the  medulla. 

36.  From  this  double  interlacing  of  fibres  results  a  cross 
action  between  the   original   and  terminal  extremity  of  all 
nerve-fibres  which  pass  through  the  medulla  —  namely,  those 
of  all  the  spinal  nerves.     Consequently,  if  the  right  hand  be 
hurt,  the  left  side  of  the  brain  feels  the  pain ;  and  if  the  left 
foot  move,  it  is  the  right  hemisphere  which  dictates  its  move- 
ment.    For  the  same  reason,  when  a  loss  of  sensation  and 
power  of  motion  affecting  the  right  side  of  the  body  alone  is 
observed,  the  physiologist  understands  that  the  brain  has  been 
invaded  by  disease  upon  its  left  side.     This  affection  is  termed 
hemiplegia,  or  the  "  half -stroke."     The  full-stroke,  which  often 
follows  the  rupture  of  a  blood-vessel  in  the  brain,  is  commonly 
called  paralysis. 

37.  The  Reflex  Action  of  the  Cord.  —  We  have  already  con- 
sidered the  cord  as  the  great  motor  and  sensory  nerve  of  the 
body,  but  it  has  another  and  extremely  important  use.     By 
virtue  of  the  gray  matter,  which  occupies  its  central  portion,  it 
plays  the  part  of  an  independent  nerve  centre.     The  spinal 
cord  not  only  conducts  some  impressions  to  the  brain,  but  it 
also  arrests  others;  and,  as  it  is  expressed,  "reflects"  them 
into  movements  by  its  own  power.     This  mode  of  nervous 
activity  is  denominated  the  reflex  action  of  the  cord. 

38.  A  familiar  example  of  this  power  of  the  cord  is  found  in 
the  violent  movements  which  agitate  a  fowl  after  its  head  has 

86.  Direction  of  the  anterior  or  motor  columns  ?    In  the  cord  itself?    In  the  medulla 
oblongata  ?    The  decussation  ? 

86.  Result  -of  the  double  interlacing  of  fibres  ?    Where  is  the  seat  of  pain  when  the  right 
hand  is  hurt  ?    The  moving  of  the  foot  ?    Loss  of  sensation  in  one  side  of  the  body  ? 

87.  What  other  important  use  has  the  cord  1    What  is  the  activity  denominated  ? 

88.  Example  of  the  fowl  ?    Centipede  ?    Frog  ?    What  do  they  prove  ? 


THE  NERVOUS  SYSTEM  239 

been  cut  off.  The  cold-blooded  animals  also  exhibit  reflex 
movements  in  an  astonishing  degree.  A  decapitated  centipede 
will  run  rapidly  forward,  and  will  seemingly  strive  to  over- 
turn, or  else  climb  over  obstacles  placed  in  its  way.  A  frog 
similarly  mutilated  will  sustain  its  headless  body  upon  its  feet, 
in  the  standing  posture,  just  as  it  might  do  if  it  were  still 
alive.  If  pushed  over,  it  will  regain  its  feet;  and  if  the  feet 
are  irritated,  it  will  jump  forward.  There  can  be  no  doubt 
that,  in  the  lower  animals,  movements  may  take  place  which 
are  completely  divorced  from  the  will,  sensation  and  conscious- 
ness ;  for  in  those  animals,  as  well  as  in  man,  these  faculties 
have  their  principal  seat  within  the  brain. 

39.  An  irritation  is  necessary,  in  most  instances,  to  awaken 
reflex  movements.     In  the  case  of  the  decapitated  fowl,  its 
muscles  are  excited  to  convulsive  action  by  reason  of  its  being 
thrown  upon  the  hard  ground  and  roughly  handled.     Let  it  be 
treated  differently,  and  the  convulsions  will  not  take  place: 
let  it  be  laid  gently  upon  soft  cotton,  and  the  body  will  remain 
comparatively  quiet.     It  may  comfort  some  people  to  know 
that  the  convulsions  which  follow  decapitation  are  not  attended 
with  pain,  nor  are  they  a  necessary  part  of  the  "  act  of  death," 
as  some  suppose. 

40.  In  the  human  body,  likewise,  actions  are  excited  that 
are  entirely  distinct  from  the  ordinary  voluntary  efforts.    It  is 
£ot  permissible,  desirable,  nor  even  necessary  to  decapitate  a 
man  that  the  body  may  be  disconnected  from  his  brain,  in 
order  to  test  the  effect  of  irritation  upon  the  spinal  cord  — 
although  the  bodies  of  beheaded  criminals  have  been  experi- 
mented upon,  and  caused  to  move  by  powerful  galvanic  bat- 
teries.     Such  experiments  are  rendered  unnecessary  by  the 
occurrence  of  certain  deplorable  cases  of  disease  and  injury, 
which  effectually  sever  all  communication  between  the  brain 
and  a  large  part  of  the  body. 

41.  Thus,  the  cord  by  an  accident  may  be  so  far  injured  as 

39.  What  is  necessary  in  most  cases  to  awaken  reflex  movements  ?    In  the  case  of  the 
fowl  ?  Convulsions  which  follow  decapitation  ? 

40.  Actions  in  the  human  body  distinct  from  voluntary  efforts  ?  J^^ 

41.  Reflex  action  after  Injury  of  the  cord  ?    Why  not  due  to  the  muscles  f   /  Or  T  H  E 


(  UNIVERSI 

\ 


240  THE  NERVOUS  SYSTEM 

to  terminate  all  sensation  and  voluntary  motion  in  the  lower 
half  of  the  body,  the  patient  seeming  lifeless  and  powerless  from 
the  waist  downward.  And  yet,  by  tickling  or  pinching  either 
foot,  the  leg  of  the  same  side  may  be  made  to  jerk,  or  even 
to  kick  with  considerable  force ;  but,  unless  the  patient  is  ob- 
serving his  limbs,  he  is  wholly  unconscious  of  these  movements, 
which  are,  therefore,  performed  independently  of  the  brain. 
And  they  are  in  nowise  due  to  the  muscles  of  the  limb ;  for, 
if  the  cord  itself  become  diseased  below  the  point  of  injury, 
the  muscles  cease  to  contract. 

42.  For  the  production  of  this  form  of  nervous  action,  three 
things  are  requisite  —  (1)  a  nerve  to  conduct  messages  from 
the  surface  of  the  body,  one  of  that  variety  formerly  described 
as  sensory,  but  which  are  now  known  to  be  incapable  of  awaken- 
ing sensation ;  (2)  a  portion  of  uninjured  spinal  cord,  which 
shall  reflect  or  convert  impressions  into  impulses ;  and  (3)  a 
motor  nerve  to  conduct  impulses  outward  to  the  muscles.    The 
power  of  the  cord  to  enforce  reflex  acts  resides  in  the  gray 
matter,  into  which  the  reflex  nerves  enter  and  from  which 
they  depart,  by  means  of  their  posterior  and  anterior  roots 
respectively. 

43.  The  Uses  of  the  Reflex  Action. — The  reflex  activity  of 
the  cord  is  exhibited  in  the  healthy  body  in  many  ways,  but 
since  it  is  never  accompanied  with  sensation,  we  do  not  readily 
recognize  it  in  our  own  bodies.     Reflex  movements  are  best 
studied  in  the  cases  of  other  persons,  when  the  conditions  en- 
able us  to  distinguish  between  acts  that  are  consciously,  and 
those  that  are  unconsciously  performed.     For  example,  if  the 
foot  of  a  person  soundly  asleep  be  tickled  or  pinched,  it  will 
be  quickly  withdrawn  from  the  irritation. 

44.  Similar  movements  may  be  observed  in  cases  where  the 
consciousness  and  sensation   are   temporarily  obliterated  by 
disease,  or  by  means  of  narcotic  poisons.     If  the  arm  of  a  per- 
son who  has  been  rendered  insensible  by  chloroform  be  raised, 

42.  What  are  the  requisites  for  the  production  of  this  form  of  nervous  action  ? 

43.  Why  do  we  not  readily  recognize  the  reflex  activity  of  the  cord  in  our  own  bodies  ? 
How  best  studied  In  others  ?    Example  ? 

44.  Similar  movements  ?    Arm  of  a  person  j     Melted  wax  or  heated  coin  on  the  hand  ? 


THE  NERVOUS  SYSTEM  241 

and  then  allowed  to  fall,  it  will  be  noticed  that  the  limb  does 
not  drop  instantly,  like  a  lifeless  member,  but  a  certain  amount 
of  rigidity  remains  in  its  muscles,  which  resists  or  breaks  the 
force  of  its  descent.  Again,  when  a  substance  like  melted 
sealing-wax,  or  a  heated  coin,  falls  upon  the  hand,  the  limb  is 
snatched  away  at  once,  even  before  the  feeling  of  pain  has 
been  recognized  by  the  brain.  When  jolted  in  a  rapidly  mov- 
ing car,  we  involuntarily  step  forward  or  backward,  so  as  to 
preserve  the  centre  of  gravity  of  the  body. 

45.  These  and  similar  acts  are  executed  by  the  same  mechan- 
ism as  that  previously  described  in  the  case  of  paralysis  from 
an  injury  of  the  spinal  cord.  The  muscles  thus  called  into 
play  are  those  which  are  ordinarily  under  the  sway  of  the  will, 
but  which  in  these  cases  act  through  this  reflex  action  of  the 
cord,  altogether  independently  of  the  will.  A  healthful  reflex 
activity  produces  an  elasticity,  or  "  tone,"  in  the  voluntary  mus- 
cular system,  which  in  a  great  measure  explains  the  existence 
in  the  young  and  vigorous  of  a  feeling  of  buoyancy  and  reserve 
power.  Its  possessor  is  restlessly  active,  and  it  may  appropri- 
ately be  said  of  him,  "he  rejoiceth  as  a  strong  man  to  run  a 
race."  But  this  reflex  energy  may  be  deficient.  This  is  true 
when  the  blood  is  poor  and  wanting  in  its  solid  ingredients,  or 
the  circulation  is  feeble;  the  muscles,  then,  are  flabby  and 
weak,  and  the  person  himself  is  said  to  be  "  nerveless,"  or  in- 
disposed to  exertion.  Shivering  from  cold  and  trembling  from 
fear  may,  in  part,  be  referred  to  a  temporary  loss  of  tone, 
resulting  from  a  powerful  impression  upon  the  brain.  (Bead 
Note  6.) 

6.  On  Nervous  Health,  or  Tone.  —  "  That  state  of  general  vigor,  which 
we  call  '  tone,'  depends  upon  the  healthy  action  of  the  nervous  centres. 
It  consists  in  the  habitual  moderate  contraction  of  the  muscles,  due  to  a 
constant  stimulus  exerted  on  them  by  the  cord,  and  is  valuable  less  for 
itself  than  as  a  sign  of  a  sound  nervous  balance.  Tone  is  maintained 
partly  by  healthful  impressions  radiated  upon  the  spinal  cord  through  the 
nerves  from  all  parts  of  the  body,  and  partly  by  the  stimulus  poured 
down  upon  it  from  the  brain.  So  it  is  disturbed  by  whatever  conveys 
irritating  or  depressing  influences  in  either  direction.  A  single  injudi- 

45.  Result  of  healthful  reflex  activity  ?    When  mny  the  reflex  energy  be  deficient? 


242  THE  NERVOUS  SYSTEM 

46.  An  excess   of  this  activity  may  also   be   observed  in 
disease.     In  this   condition,  the   excitability  of  the   cord   is 
unnaturally  aroused,  and  frequent  and  violent  movements*  of 
the  limbs  and  body,  called  convulsions,  are  the  result.     The 
convulsions  of  young  children,  and  the  nervous  agitation  of 
chorea,  or  St.  Vitus's  dance,  are  reflex  in  character,  as  are  also 
the  symptoms  attending  poisoning  by  strychnine,  and  those 
terrible  diseases,  tetanus,  or  "locked  jaw,"  and  hydrophobia. 
The  severity  of  the  convulsions  is  not  the  same  in  all  cases  of 
these  disorders ;  but,  in  those  last  mentioned,  the  most  violent 
spasmodic  movements  are  provoked  by  the  slightest  form  of 
irritation  —  such  as  the  sound  of  pouring  water,  the  sight  of 
any  glittering  object,  the  glancing  of  a  mirror,  the  contact 
of  cool  air,  or  even  the  touch  of  the  bed-clothes. 

47.  Another  variety  of  reflex  motions  takes  place  in  certain 
involuntary  muscles,  and  over  these  the  cord  exercises  supreme 
control.     They  are  principally  those  movements  which  aid  the 
performance  of  digestion  and  nutrition,  the  valve-action  of  the 
pylorus,  and  other  movements  of  the  stomach  and  intestines. 

cious  meal,  a  single  sleepless  night,  a  single  passion  or  piece  of  bad  news, 
will  destroy  it.  On  the  other  hand,  a  vivid  hope,  a  cheerful  resolve,  an 
absorbing  interest  will  restore  it  as  if  by  magic.  For  in  man,  these  lower 
officers  in  the  nervous  hierarchy  draw  their  very  breath  according  t«  the 
bidding  of  the  higher  powers.  But  the  dependence  of  the  higher  on  the 
lower  is  no  less  direct.  The  mutual  action  takes  place  in  each  line.  A 
chief  condition  of  keeping  the  brain  healthy  is  to  keep  these  unconscious 
nervous  functions  in  full  vigor,  and  in  natural  alterations  of  activity  and 
repose.  We  see  evidence  of  this  law  in  the  delightful  effect  of  a  cheerful 
walk  after  a  depressed  or  irritated  state  of  mind.  Every  part  of  the  ner- 
vous system  makes  its  influence  felt  by  all  the  rest.  A  sort  of  constitu- 
tional monarchy  exists  within  us  ;  no  power  in  this  small  state  is  absolute 
or  can  -escape  the  checks  and  limitations  which  the  other  powers  impose. 
Doubtless  the  Brain  is  King,  but  Lords  and  Commons  have  their  seats 
below  and  guard  their  privilege  with  jealous  zeal.  If  the  '  constitution ' 
of  your  personal  realm  is  to  be  preserved  intact,  it  must  be  by  the  efforts 
of  each  part,  lawfully  directed  to  a  common  end."  —  Hinton  on  Health 
and  its  Condition. 


46.  Excess  of  this  activity  in  disease  ?    Hydrophobia,  etc.  ?    The  difference  in  severity 
of  the  convulsions  ? 

47.  Another  variety  of  reflex  motions  ?    What  are  they  ?    What  is  stated  of  the  mind 
in  connection  with  these  movements  ? 


THE  NERVOUS  SYSTEM  243 

In  these  movements  the  mind  shares  no  part.  And  it  is  well 
that  this  is  so ;  for,  since  the  mind  is  largely  occupied  with 
affairs  external  to  the  body,  it  acts  irregularly,  becomes 
fatigued,  and  needs  frequent  rest.  The  spinal  cord,  on.  the 
contrary,  is  well  fitted  for  the  form  of  work  on  which  depends 
the  growth  and  support  of  the  body,  as  it  acts  uniformly,  and 
with  a  machine-like  regularity. 

48.  These  operations  are  not  accompanied  by  consciousness ; 
for,  as  a  general  rule,  the  attention  is  only  called  to  them  when 
they  become  disordered.     Many  a  person  does  not  know  where 
his  stomach,  is  situated  until  he  discovers  its  position  by  reason 
of  a  feeling  of  distress  within  it,  produced  by  giving  that 
organ  improper  work  to  perform.     In  this  manner  the  higher 
and  nobler  faculties  of  the  mind  are  liberated  from  the  simple 
routine  duties  of  the  body,  and  we  are  thus  left  to  direct  the 
attention,  the  reason,  and  the  will  to  the  accomplishment  of 
the  great  ends  of  our  existence.     If  it  were  otherwise,  we 
could  only  find  time  to  attend  to  our  ordinary  physical  wants. 

49.  The  objects  of  the  reflex  activity  of  the  cord  are  three- 
fold.    In  the  first  place,  it  acts  as  the  protector  of  man  in  his 
unconscious  moments.     It  is  his  unseen  guardian,  always  ready 
to  act,  never  growing  weary,  and  never  requiring  sleep.     Nor 
does  its  faithful  action  wholly  cease  with  the  cessation  of  life 
in  other  parts.     In  the  second  place,  it  is  the  regulator  of 
numerous  involuntary  motions  that  are  necessary  to  the  nutri- 
tion of  the  body.     Here  its  actions  are  entirely  independent 
of  the  brain,  and  are  performed  in  a  secret  and  automatic 
manner.     And,  thirdly,  it  acts  as  a  substitute,  and  regulates 
involuntary  movements  in  the  muscles  usually  under  the  influ- 
ence of  the  will.     It  thus  takes  the  place  of  the  higher  facul- 
ties in  performing  habitual  acts,  and  permits  them  to  extend 
their   operations   more   and  more   beyond  the   body   and  its 
material  wants.^ 

50.  The  Functions  of  the  Medulla  Oblongata.  —  The  prolonga- 

48.  Consciousness  in  these  operations  ?    Physical  wants  ? 

49.  How  many  objects  may  the  reflex  activity  be  said  to  have  ?    State  the  first.    The 
second.    The  third. 

60.   How  does  the  medulla  oblongata  resemble  the  cord  ? 


244  THE  NERVOUS  SYSTEM 

tion  of  the  spinal  cord  within  the  skull  has  been  previously 
spoken  of  as  the  medulla  oblongata.  It  resembles  the  cord,  in 
being  composed  of  both  white  and'  gray  matter,  and  in  con- 
ducting sensory  and  motor  influences.  It  likewise  gives  rise 
to  certain  nerves,  which  are  here  called  cranial  nerves  (from 
cranium,  the  skull).  All  except  two  of  these  important  nerves 
spring  from  the  medulla,  or  the  parts  immediately  adjoining 
it ;  the  exceptions  are  the  two  nerves  taking  part  in  the  special 
senses  of  sight  and  smell,  which  nerves  have  their  origin  at 
the  base  of  the  cerebrum. 

51.  The  decussation,  or  crossing  of  the  motor  columns,  has 
been  previously  described,  when  treating  of  the  direction  of 
the  nerve-fibres  of  the  cord;  and  the  singular  fact  has  been 
alluded  to,  that  when  one  side  of  the  brain  is  injured,  its 
effects  are  limited  to  the  opposite  side  of  the  body.     One  more 
fact  remains  to  be  observed  in  this  connection,  namely,  this 
cross  action  does  not  usually  take  place  in  the  cranial  nerves. 
Accordingly,  when  apoplexy,  or  the  rupture  of  a  blood-vessel, 
occurs  in  the  right  hemisphere  of  the  cerebrum,  the  left  side 
of  the  body  is  paralyzed,  but  the  right  side  of  the  face  is 
affected ;  this  is  because  that  part  of  the  body  is  supplied  by 
the  cranial  nerves. 

52.  A  portion  of  the  medulla  presides  over  the  important 
function  of  respiration,  and  from  it  arises  the  pneumogastric 
nerve,  so  called  because  its  branches  serve  both  the  lungs  and 
stomach.     The  feelings  of  hunger,  thirst,  and  the  desire  for 
air  are  aroused  by  means  of  this  nerve.     The  wounding  of  the 
gray  matter  of  the  medulla,  even  of  a  small  portion  of  it, 
near  the  origin  of  the  pneumogastric  nerve,  at  once  stops  the 
action  of  the  lungs  and  causes  death.     In  consequence  of  the 
importance  of  this  part,  it  has  been  termed  the  "  vital  knot." 
We  find,  also,  that  its  location  within  the  skull  is  exceedingly 
well  protected,  it  being  quite  beyond  the  reach  of  any  ordinary 
form  of  harm  from  without. 


51.  What  final  fact  is  observed  in  the  crossing  of  the  motor  columns  ? 

52.  The  pneumogastric  nerve  ?    The  feelings  aroused  by  it  ?    The  "  vital  knot  ? ' 


THE  NERVOUS   SYSTEM  245 

53.  The  Functions  of  the  Cranial  Ganglia.  —  The  uses  of  the 
smaller  gray  masses  lying  at  the  base  of  the  brain  are  not 
well  ascertained ;  and,  on  account  of  their  position,  so  remote 
from  the  surface,  it  would  at  first  seem  well-nigh  impossible 
to  study  them.     But,  from  the  results  following  diseases  in 
these  parts,  and  from  experiments  upon  inferior  animals,  they 
are  becoming  gradually  better  understood ;  and  there  is  reason 
to  believe  that  eventually  the  physiological  office  of  each  part 
will  be  clearly  ascertained  and  defined.     It  is  believed,  how- 
ever, but  not  absolutely  proved,  that  the  anterior  masses,  like 
the  anterior  roots  of  the  spinal  nerves  and  the  anterior  col- 
umns of  the  cord,  are  concerned  in  the  production  of  motion ; 
in  fact,  that  they  are  the  central  organs  of  that  function.     The 
posterior  gray  masses  are,  on  the  contrary,  supposed  to  be  the 
seat  of  sensation. 

54.  The  Function  of  the  Cerebellum. — The  function  of  the 
cerebellum,  or  "  little  brain,"  is  the  direction  of  the  movements 
of  the  voluntary  muscles.     When  this  organ  is  the  seat  of 
disease  or  injury,  it  is  usually  observed  that  the  person  is 
unable  to  execute  orderly  and  regular  acts,  but  moves  in  a 
confused  manner  as  if  in  a  state  of  intoxication.     Like  the 
larger  brain,  or  cerebrum,  it  appears  to  be  devoid  of  feeling ; 
but  it  takes  no  part  in  the  operations  of  the  mind. 

55.  The  Function  of  the  Cerebrum.  —  The  cerebrum,  or  brain 
proper,  is  the  seat  of  the  mind ;.  or,  speaking  more  exactly,  it 
is  the  material  instrument  by  which  the  mind  acts ;  and,  as  it 
occupies  the  highest  position  in  the  body,  so  it  fulfils  the  lofti- 
est uses.     All  the  other   organs   are   subordinate  to  it:    the 
senses  are  its  messengers,  which  bring  it  information  from  the 
outer  world,  and  the  organs  of  motion  are  its  servants,  which 
execute  its  commands.     Here,  as  in  the  nervous  apparatus  of 
lower  grade  already  considered,  the  gray  matter  is  the  element 
of  power;  and  in  proportion   as  this  substance  increases  in 
extent,  and  in  proportion  to   the  number  of  convolutions  in 
the  hemispheres,  do  the  mental  faculties  expand. 

53.  The  uses  of  the  smaller  gray  masses  at  the  base  of  the  brain  ? 

54.  Function  of  the  cerebellum  ?    When  it  is  diseased  ? 

55.  Where  is  the  seat  of  the  mind  ?    The  subordination  of  the  other  organs  ?    The  gray 
matter? 


246  THE  NERVOUS  SYSTEM 

56.  There  have  been  a  few,  but  only  a  few,  men  of  distin- 
guished ability  whose  brains  have  been  comparatively  small  in 
size  —  the  rule  being  that  great  men  possess  large  brains.    The 
relative  weight  of  the  brain  of  man,  as  compared  with  the 
weight  of  the  body,  does  not,  in  all  instances,  exceed  that  of 
the  inferior  animals ;  the  canary  and  other  singing-birds  have 
a  greater  relative  amount  of  nervous  matter  than  man;  but 
man  surpasses   all  other  creatures  in  the  size  of  the  hemi- 
spheres of  the  cerebrum,  and  in  the  amount  of  gray  substance 
which  they  contain.  (Bead  Notes  7  and  8.) 

57.  It  is  a  singular  fact  that  this  cerebral  substance  is  insen- 
sitive, and  may  be  cut  without  causing  pain.     The  removal  of 

7.  The  Alliance  of  Mind  and  Body.  —  "The  regular  routine  of  our 
daily  life  is  the  counterpart  of  the  mental  routine.     A  healthy  man  wakens 
in  the  morning  with  a  flush  of  spirits  and  energy  ;  his  first  meal  confirms 
and  reinforces  the  state.      The  mental  powers  and  susceptibilities  are 
then  at  a  maximum ;  as  the  nutrition  is  used  up  in  the  system  they 
gradually  fade,  but  may  be  renewed  once  and  again  by  refreshment  and 
brief  remission  of  toil.    Towards  the  end  of  the  day  lassitude  sets  in,  and 
fades  into  the  deep  unconsciousness  of  healthy  sleep.  .  .  .     The  influ- 
ences that  affect  the  body  extend  not  only  to  the  .grosser  modes  of  feel- 
ing, and  to  such  familiar  exhibitions  as  after-dinner  oratory,  but  also  to 
the  highest  emotions  —  love,  anger,  aesthetic  feeling,  and  moral  sensibility. 
Health  keeps  an  Atheist  in  the  dark.     Bodily  affliction  is  often  the  cause 
of  a  total  change  in  the  moral  nature."  —  Bain's  Mind  and  Body. 

8.  Large  Brains.  —  "  As  a  rule  the  size  of  the  brain  is  proportional  to 
the  mental  development  in  human  beings.     The  rule  is  not  strictly  main- 
tained in  every  instance ;  occasionally  a  stupid  man  has  a  larger  brain 
than  a  clever  man.     But  these  are  only  individual  exceptions  to  a  prevail- 
ing arrangement.     The  following  are  the  brain  weights  of  several  distin- 
guished men : 


Cuvier 64.5  oz. 

Abercrombie 63.    " 

Daniel  Webster. ,   .  53.5  " 


Lord  Campbell 53.5  oz. 

Agassiz 53.4  " 

De  Morgan 52.7  " 


"  The  average  male  brain  in  Europeans  is  49.5  oz. ;  the  female,  44  oz. 
Among  idiots  the  weights  have  run  from  27  to  8.5  oz.  The  brains  of  the 
insane  are  below  the  average  of  the  sane.  Tall  men,  as  a  rule,  have 
larger  brains  than  small  men."  — Bain's  Mind  and  Body. 


56.  What  is  stated  of  men  in  connection  with  the  size  of  their  brain  ?  With  the  brains 
of  other  animals  ? 

5T.  Sensitiveness  of  the  brain  substance?  The  removal  of  a  portion  of  the  brain? 
State  the  remarkable  case  mentioned. 


THE  NERVOUS  SYSTEM  247 

a  considerable  quantity  of  the  brain  has  taken  place,  as  the 
result  of  accident,  without  causing  death,  and  without  even 
affecting  seriously  the  intellect.  A  remarkable  case  of  injury 
of  the  brain  is  recorded,  in  which,  from  the  accidental  explo- 
sion of  gunpowder  used  in  blasting  a  rock,  the  "  tamping-iron  " 
was  driven  directly  through  the  skull  of  a  man.  This  iron 
rod,  three  feet  and  seven  inches  long,  an  inch  and  a  quarter 
in  diameter,  and  weighing  more  than  thirteen  pounds,  entered 
the  head  below  the  ear  and  passed  out  at  the  top  of  the  skull, 
carrying  with  it  portions  of.  the  brain  and  fragments  of  bone. 
The  man  sustained  the  loss  of  sight  on  one  side,  but  otherwise 
recovered  his  health  and  the  use  of  his  faculties.  Moreover, 
disease  has  occurred,  compromising  a  large  portion  of  the 
brain,  without  impairing  the  faculties  of  the  mind,  when  the 
disease  was  limited  to  one  side  only.  (Read  Note  9.) 

9.  The  Emotions  Influence  the  Bodily  Health.  —  "The  exciting  emo- 
tions which  are  pleasurable,  such  as  joy  and  hope,  are  of  a  kind  that 
seldom  tend  to  a  dangerous  excess,  and  may  be  regarded  as  exercising 
generally  an  eminently  healthful  influence  upon  the  body.  Hilarity  is  a 
great  refresher  and  strengthener  of  life.  Laughter  is  a  wholesome  exer- 
cise, which,  beginning  at  the  lungs,  diaphragm,  and  connected  muscles,  is 
continued  to  the  whole  body,  'shaking  the  sides,'  and  causing  that  jelly- 
like  vibration  of  the  frame  of  which  we  are  so  agreeably  conscious  when 
under  its  influence.  The  heart  beats  more  briskly,  but  with  a  safe  regu- 
larity of  action,  and  sends  the  blood  to  the  smallest  and  most  distant 
vessel.  The  face  glows  with  warmth  and  color,  the  eye  brightens,  and 
the  temperature  of  the  whole  body  is  moderately  raised.  With  the  uni- 
versal pleasurable  sensation  there  comes  a  disposition  of  every  organ  to 
healthy  action.  When  hilarity  and  its  ordinary  expression  of  laughter 
become  habitual,  the  insensible  perspiration  of  the  skin  is  increased,  the 
breathing  quickened,  the  lungs  and  chest  expanded,  the  appetite  and 
digestion  strengthened,  and  nutrition  consequently  increased.  The  old 
proverb,  'Laugh  and  grow  fat,'  states  a  scientific  truth.  The  influence 
of  laughter  upon  the  body  is  recognized  by  Shakespeare,  in  his  descrip- 
tion of  the  'spare  Cassius'  —  '  Seldom  he  smiles.'  'To  be  free-minded 
and  cheerfully  disposed  at  hours  of  meat,  and  sleep,  and  exercise,  is  one 
of  the  best  precepts  of  long-lasting.'  Such  is  the  testimony  of  Lord  Bacon 
to  the  favorable  influence  of  the  pleasurable  emotions  upon  the  body. 
The  depressing  emotions,  such  as  fear,  anxiety,  and  grief,  are  always 
fatal  to  health,  and  frequent  causes  of  death.  There  is  an  Eastern 
apologue  which  describes  a  stranger  on  the  road  meeting  the  Plague 
coming  out  of  Bagdad.  '  You  have  been  committing  great  havoc  there,' 
said  the  traveler,  pointing  to  the  city.  '  Not  so  great,'  replied  the  Plague. 


248  THE  NERVOUS  SYSTEM 

58.  Impressions   conveyed    to   the    hemispheres    froaa    the 
external  world  arouse  the  mental  operations  called  thought, 
emotion,  and  the  will.     These  are  the  godlike  attributes  which 
enable  man  to  subjugate  a  world,  and  afterwards  cause  him 
to  "sigh  for  other,  worlds  to  conquer;"  which   enable   him 
to  acquaint  himself  with  the  properties  of  planets  millions 
of  miles  distant  from  him,  and  which  give  him  that  creative 
power  by  which  he  builds  and  peoples  the   new  worlds   of 
poetry  and  art. 

59.  All  these  mental  acts,  and  many  others,  are  developed 
through  the  action  of  the  brain;  not  that  the  brain  and  the 
mind  are  the  same,  or  that  the  brain  secretes  memory,  imagi- 
nation, or   the   ideas   of  truth   and  justice,  as   the   stomach 
secretes  gastric  juice.     But  rather,  as  the  nerve  of  the  eye, 
stimulated  by  the  subtile  waves  of  light,  occasions  the  notion 
of  color,  so  the  brain,  called  into  action  by  the  mysterious 
influences  of  the  immaterial  soul,  gives  rise  to  all  intellectual, 
emotional,  and  voluntary  activities. 

60.  The  cerebrum,  according  to  our  present  knowledge  of 
it,  must  be  regarded  as  a  single  organ,  which  produces  different 
results,  according  as  it  is  acted  upon  by  the  immaterial  mind 
in  different  ways.     Recent  investigations,  however,  seem  to 
prove  that  the  faculty  of  language  is  dependent  upon  a  small 
part  of  the  left  hemisphere  of  the  cerebrum  near  the  temple. 
At  least,  in  almost  every  instance  where  this  part  is  diseased, 
the  patient  can  no  longer  express  himself  in  speech  and  writing. 
(Head  Note  10.) 

4 1  only  killed  one-third  of  those  who  died ;  the  other  two-thirds  killed 
themselves  with  fright.'  "  —  The  Book  of  Health. 

10.  Mental  Exercise  Necessary  to  Perfect  Health.  —  "The  improve- 
ment of  the  memory  is  a  familiar  instance  of  an  increase  of  mental  power 
produced  by  exercise  ;  and  the  beating  sense  of  fulness  and  quickened 
circulation  in  the  head  induced  by  intense  study  or  thought  shows  that 
an  organic  process  goes  on  when  the  brain  is  in  activity,  similar  to  that 
which  takes  place  in  the  muscular  system  under  exercise.  On  the  con- 
trary, when  the  organ  is  little  used,  little  expenditure  of  its  power  and 


58.  Thought,  emotion,  and  will  ?    What  power  do  they  give  us  ? 

59.  Are  the  brain  and  the  mind  identical  ? 

60.  What  do  we  know  of  the  cerebrum  and  its  powers  ? 


THE  NERVOUS  SYSTEM  249 

61.  The  Reflex  Action  of  the  Brain.  — The  reflex  function  of 
the  organs  within  the  skull  is  very  active  and  important.     Like 
that  of  the  cord,  it  protects  the  body  by  involuntary  move- 
ments, it  regulates  the  so-called  vegetative  acts,  and  it  takes 
the  place  of  the  will  in  controlling  the  voluntary  muscles, 
when  the  attention  is  turned  in  other  directions.     The  reflex 
power  of  the  medulla  governs  the  acts  of  respiration,  which 
are  absolutely  and  continuously  essential  to  life.     Kespiration 
is,  as  we  have  seen,  partly  under  the  influence  of  the  will ;  but 
this  is  due  in  part  to  the  fact  that  respiration  is  indirectly  con- 
cerned in  one  of  the  animal  functions  —  that  of  speech. 

62.  Reflex  action  also  occasions   coughing   and   sneezing, 
whenever  improper  substances  enter  the  air-passages.     Wink- 
ing is  an  act  of  the  same  sort,  and  serves  both  to  shield  the 
eyes  from  too  great  glare  of  light,  and  to  preserve  them  by 
keeping  the  cornea  moist.     Looking  at  the  sun  or  other  strong 
light,  causes  sneezing  by  reflex   action.     Laughing,  whether 
caused  by  tickling  the  feet  or  by  some  happy  thought,  and 
also  sobbing,  are  reflex  acts,  taking  place  by  means  of  the 
respiratory  muscles. 

63.  Certain  of  the  protective  reflex  movements  call  into 
play  a  large  number  of  muscles,  as  in  the  balancing  of  the 
body  when  walking  along  a  narrow  ledge,  or  on  a  slippery 
pavement.     The  dodging  motion  of  the  recruit,  when  the  first 
cannon  ball  passes  over  his  head,  is  reflex  and  involuntary. 

substance  takes  place,  little  blood  and  little  nervous  energy  are  required 
for  its  support,  and,  therefore,  little  is  sent ;  nutrition  in  consequence 
soon  becomes  languid,  and  strength  impaired.  To  all  these  laws  the 
brain  is  subject  equally  as  the  rest  of  the  body.  Freque'nt  and  regular 
exercise  gives  it  increased  susceptibility  of  action,  with  power  to  sustain 
it,  the  nervous  energy  acquiring  strength  as  well  as  the  vascular.  Dis- 
use of  its  functions,  or,  in  other  words,  inactivity  of  intellect  and  of  feel- 
ing, impairs  its  structure  and  weakens  the  several  powers  which  it  serves 
to  manifest.  The  brain,  therefore,  in  order  to  maintain  its  healthy  state, 
requires  to  be  duly  exercised."  — Barlow  on  Physical  Education. 


61.  The  reflex  function  of  the  organs  within  the  skull  ?     The  reflex  power  of  the 
medulla?    Respiration? 

62.  What  else  does  reflex  action  occasion  ?    Winking  ?    Other  examples  ? 

63.  Muscles  called  into  play  by  certain  reflex  movements  ?    The  somnambulist  ? 


250  THE  NERVOUS  SYSTEM 

The  fact  that  these  involuntary  reflex  acts  are  performed  with 
great  precision,  will  explain  why  it  is  that  accidents  seldom 
befall  the  somnambulist,  or  sleep-walker,  although  he  often 
ventures  in  the  most  perilous  places. 

64.  Walking,  sitting,  and  other  acts  of  daily  life,  become 
automatic,  or  reflex,  from  habit;  the  mind  is  seldom  directed 
to  them,  but  delegates  their  control  to  the  medulla  and  spinal 
cord.  Thus  a  person  in  walking  may  traverse  several  miles 
while  absorbed  in  thought,  or  in  argument  with  a  companion, 
and  yet  be  conscious  of  scarcely  one  in  a  thousand  of  the  acts 
that  have  been  necessary  to  carry  his  body  from  one  point  to 
another.  By  this  admirable  and  beautiful  provision  the  mind 
is  released  from  the  charge  of  the  ordinary  mechanical  acts  of 
life,  and  may  devote  itself  to  the  exercise  of  its  nobler  facul- 
ties. And  it  is  worthy  of  notice,  that  the  more  these  faculties 
are  used,  the  more  work  does  the  reflex  function  assume  and 
perform;  and  thus  the  employment  of  the  one  insures  the 
improvement  of  the  other.  (Head  Notes  11  and  12.) 

11.  Automatic  Action  of  the  Brain.  —  "A  large  part  of  our  mental 
activity  consists  of  this  unconscious  work  of  the  brain.  There  are  many 
cases  in  which  the  mind  has  obviously  worked  more  clearly  and  more 
successfully  in  this  automatic  condition,  when  left  entirely  to  itself,  than 
when  we  have  been  cudgeling  our  brains,  so  to  speak,  to  get  the  solution. 
An  instance,  well  authenticated,  is  related  of  a  college  student ;  he  had 
been  attending  a  class  in  mathematics,  and  the  professor  said  to  his 
students  one  day :  '  A  question  of  great  difficulty  has  been  referred  to  me 
by  a  banker  —  a  very  complicated  question  of  accounts,  which  they  have 
not  themselves  been  able  to  bring  to  a  satisfactory  issue,  and  they  have 
asked  my  assistance.  I  have  been  trying,  and  I  cannot  resolve  it.  I 
have  covered  whole  sheets  of  paper  with  calculations,  and  have  not  been 
able  to  make  it  out.  Will  you  try  ? '  He  gave  it  to  them  as  a  sort  of 
problem,  and  said  he  would  be  extremely  obliged  to  any  one  who  would 
bring  him  the  solution  by  a  certain  day.  This  gentleman  tried  it  over  and 
over  again ;  he  covered  many  slates  with  figures,  but  did  not  succeed. 
He  was  '  put  on  his  mettle,'  and  determined  to  achieve  the  result.  But 
he  went  to  bed  on  the  night  before  the  solution  was  to  be  given  in  with- 
out having  succeeded.  In  the  morning,  when  he  went  to  his  desk,  he 
found  the  whole  problem  worked  out  and  in  his  own  hand.  He  had 
risen  in  the  night  and  unconsciously  worked  it  out  correctly,  as  the 


64.  What  is  said  of  walking  and  other  acts  in  connection  with  the  office  performed  by 
the  medulla  and  spinal  cord  ? 


THE  NERVOUS  SYSTEM  251 

65.  Effects  of  Alcohol  upon  the  Brain.  —  The  brain  under  the 
influence  of  small  and  occasional  doses  of  alcohol  shows  no 
serious  changes  other  than  an  increased  supply  of  blood  to  the 
head.  Very  serious  changes,  however,  result  from  the  habitual 
use  of  alcohol ;  the  brain  becomes  harder  and  tougher  than  is 
natural,  and  its  cell  elements  show  a  wasting  away,  its  sub- 
stance appears  shrunken,  and  an  undue  amount  of  watery  fluid 
fills  the  cavities  in  the  brain,  in  order  to  make  up  the  dimin- 
ished bulk.  The  blood-vessels  of  the  brain  are  sometimes 
found  to  be  in  a  weakened  condition,  and  from  this  various 
cliseased  conditions  may  follow.  (Bead  Note  13.) 

result  proved ;  and  what  is  more  curious  still,  the  process  was  very 
much  shorter  than  any  of  his  previous  trials."  —  W.  B.  Carpenter  on 
Unconscious  Action. 

12.  The  Mind  should  be  Intelligently  Cultivated.  —  "  The  cultivation 
of  the  mind  should  be  carried  on  with  judgment,  and  in  due  submission 
to  the  requirements  of  the  body.     If  study  be  the  duty  of  the  youth,  let 
him  pursue  it  diligently,  but  with  such  intervals  of  rest  and  bodily  exer- 
tion as  may  maintain  good  appetite  and  health.  - 

"The  proportion  of  hours  of  study  and  bodily  exercise  may  vary  with 
the  degree  of  mental  work,  the  healthfulness  of  the  room  and  surround- 
ing air,  the  natural  strength  of  the  body,  and  the  degree  of  health  ;  but 
as  a  general  rule  it  may  be  doubted  whether  any  young  person  can  sit  at 
close  study  for  more  than  two  hours  at  a  time  without  requiring  bodily 
exertion  to  sustain  vital  action,  and  rest  to  recruit  the  mind.  Two  hours' 
mental  work,  and  a  quarter  to  half  an  hour's  bodily  exercise,  will  be 
quite  compatible  with  the  greatest  progress  in  study. 

"  Moreover,  it  may  be  doubted  whether  such  a  student  can  work  with 
advantage  for  more  than  eight  hours  a  day,  in  addition  to  the  intervals  of 
rest,  for  the  issue  will  not  turn  on  the  number  of  hours  devoted  to  work, 
but  the  intensity  of  the  attention  given. "—  Edward  Smith  on  Health. 

13.  Trembling  due  to  Alcohol  —  "  Another  condition  is  trembling  due 
to  alcohol.     The  hands  are  shaky,  or  unsteady,  even  when  at  rest,  or  if 
the  hand  is  held  out  it  is  seen  to  vibrate  slightly,  or  in  more  advanced 
condition, '  shakes  like  an  aspen  leaf.'     I  have  seen  this  in  a  spirit-drinker, 
a  barber,  as  almost  the  only  symptom  :  he  worked  night  and  day,  in  shav- 
ing, and  to  '  steady  his  hand,'  partook  repeatedly  of  spirits  —  at  first  to 
relieve  fatigue  and  then,  because  he  saw  that  if  he  discontinued,  his  hand 
was  too  shaky  to  use  the  razor.     Complete  abstinence  from  alcohol  and 
strong  coffee  quite  removed  his  tremblings  and  his  desire  for  spirits."  — 
Dr.  W.  8.  Greenfield. 


66.  How  is  the  brain  changed  by  alcohol  f 


252  THE  NERVOUS  SYSTEM 

66.  Effects  of  Alcohol  on  the  Mind.  —  Alcohol  produces  an 
artificial  insanity,  in  which,  according  to  the  quantity  taken, 
the  various  types  of  mental  diseases  are  distinctly  manifest. 
The  perceptions  are  bewildered,  there  is  sleeplessness,  loss  of 
memory,  delusion,  clouded  reasoning   power,  and  benumbed 
moral  sense  following  in  the  train  of  alcohol  drinking.     There 
is  also  a  monomania  caused  by  the  prolonged  use  of  alcohol  — 
a  craving  for  drink  that  knows  no  bounds,  and  but  rarely  a 
cure  ;  this  is  dipsomania,  or  thirst-madness.     (Head -Note  14.) 

67.  The  Impairment  of  the  Will.  —  The  direct  result  of  the. 
taking  of  alcohol  is  seen  in  the  loss  of  self-control.    "  The  worst 
estate  of  man  is  that  wherein  he  loses  the  knowledge  and  gov- 
ernment of  himself."     It  is  in  the  formation  of  the  drinking 
habit  that  alcohol  too  often  works  the  absolute  ruin  of  its  devo- 
tee, in  both  body  and  mind.     It  is  apt  to  be  a  continuous  habit, 
having  for  its  sequel  the  dethronement  of  the  will.     It  may  be 
stated,  as  the  rule,  that  after  forty  years  of  age,  a  man  who 
has  formed  this  habit  is  unequal  by  his  own  strength  of  will  to 
abandon  it.     Many  men  of  fine  intellectual  capacity  and  amia- 
ble qualities  have  become  intemperate,  and  have  so  continued, 
as  long  as  their  efforts  to  get  free  again  have  not  been  supple- 
mented by  outside  and  enforced  restraint.*     It  is  for  such  as 
these  that  inebriate  asylums   have  been  built.      Other  hard 
drinkers  drift  into  violence  and  crime,  and  finally  find  a  cura- 

14.  Alcohol  a  Poison  of  the  Intellect.  —  "In  the  normal  state  of  a 
man's  mind,  all  the  faculties,  the  imagination,  the  judgment,  the  memory, 
the  association  of  ideas,  are  regulated  by  another  superior  faculty,  viz., 
the  attention.  The  attention  of  the  will  is  the  man  himself  ;  it  is  the  ego 
which,  being  in  the  full  possession  of  the  resources  of  which  it  disposes, 
takes  them  where  it  will,  when  it  will,  to  do  whatever  it  pleases.  Now  in 
drunkenness,  even  at  the  very  beginning,  the  will  and  the  attention  have 
disappeared.  Nothing  is  left  but  the  imagination  and  the  memory,  which, 
left  to  themselves,  without  regulation  and  without  guides,  produce  the 
most  irrational  results.  " —  Charles  Eichet. 

*  "  Alcohol  in  small  doses  super-excites  certain  intellectual  faculties  — 
the  imagination,  the  memory,  and  the  association  of  ideas  ;  but  it  para- 
lyzes others,  especially  the  will,  the  reflection,  and  judgment.  Yet,  with 


66.  What  changes  are  noticed  in  the  mind  ? 

67.  Give  effect  of  alcohol  upon  the  will. 


THE  NERVOUS  SYSTEM  253 

tive  restraint  within  prison  walls.  The  benumbing  effects  of 
drinking  habits  upon  the  moral  being  of  man  is  universally 
known.  "  All  delicacy,  courtesy,  and  self-respect  are  gone ;  the 
sense  of  justice  and  of  right  is  faint  or  quite  extinct ;  there 
is  no  vice  into  which  the  victim  of  drunkenness  does  not  easily 
slide,  and  no  crime  from  which  he  can  be  expected  to  refrain. 
Between  this  condition  and  insanity  there  is  but  a  single  step," 
and  death,  in  a  worldly  sense  a  deliverance,  in  spite  of  many 
an  effort  to  rally,  "  terminates  the  miserable  scene ;  one  by  one 
lights  have  been  removed  from  the  banquet  of  folly,  and  the 
last  is  now  extinguished."  (Head  Notes  15  and  16.) 

68.  An  illustration  of  the  disadvantage  of  drunkenness  to 
the  moral  tone  of  a  community  may  be  drawn  from  the  results 

of  the  labors  of  Father  Mathew,  about  forty  years  ago,  as  a 

» 

a  stronger  dose  all  trace  of  intelligence  disappears.  When  old  Sly  is 
stretched  on  the  ground  insensible  from  drink  and  snoring  in  the  mud, 
he  excites  compassion  and  disgust : 

O  monstrous  beast !  how  like  a  swine  he  lies ! 

Grim  death,  how  foul  and  loathsome  is  thine  image  ! " 

Charles  Richet,  in  Revue  des  Deux  Mondes. 

15.  Drunkenness  and  Insanity.  —  "  The  connection  between  drunken- 
ness and  crime  and  drunkenness  and  poverty,  is  close  and  unvarying  in 
its  effect  upon  society.     The  remarkable  increase  of  insanity  in  recent 
years  may  in  part  be  traced  to  the  use  of  intoxicating  beverages.    It  has 
been  asserted  that  at  least  seven-tenths  of  all  the  crime  and  poverty  and 
calamity  to  the  people  of  the  United  States  spring  from  the  abuse  of 
liquors."  —  Dr.  J.  E.  Reeves. 

16.  The  Effects  of  Mild  Stimulation.  —  "  Words  of  caution  to  young 
men  concerning  the  injurious  effects  of  tobacco,  as  well  as  indulgence  in 
wine  or  the  pleasures  of  the  table,  elicit,  in  ninety-nine  out  of  one  hun- 
dred cases,  the  reply,  '  It  does  not  hurt  me.'     Does  not  hurt  you !    Wait 
and  see.    In  years  to  come,  when  you  ought  to  be  in  your  prime,  you 
will  be  a  poor,  nervous,  irritable,  nerve-dried  creature.    Your  hands  will 
tremble,  your  head  will  ache,  your  sleep  be  fitful  and  disturbed,  your 
digestion  impaired  — in  short,  the  unnatural  and  transient  pleasure  at 
one  end  of  your  life  will  be  more  than  counterbalanced  by  the  discomfort 
and  misery  at  the  other.     It  is  a  truth  of  the  greatest  moment,  which 
ought  to  be  so  impressed  upon  the  mind  as  to  be  always  rising  up  within 
it,  that  transgressions  of  the  laws,  of  health,  not  punished  at  one  end  of 
life,  are  sure  to  be  at  the  other."  — J.  R.  Slack  on  the  Ten  Laws  of 
Health.  

68.  Give  results  of  Father  Mathew's  work. 


254  THE  NERVOUS  SYSTEM 

temperance '  reformer.  In  the  five  years  — 1838-1842  —  the 
consumption  of  whiskey  in  Ireland  fell  50  per  cent. ;  the  crimes 
of  violence  falling  from  64,520  to  47,027,  and  executions  from 
59  in  the  first  year  to  1  in  the  last  year.  (Read  Note  17.) 

69.  The  Poisonous  Effects  of  Alcohol. — Alcohol  is,  in  the 
main,  a  narcotic  poison  in  its  effect  upon  human  beings, 
although  the  visible  results  vary  immensely  according  to  the 
quantity  taken.  If  a  sufficient  quantity  is  taken  to  cause  any 
visible  result,  a  condition  known  as  stimulation  is  observed.* 
If  an  extremely  large  dose  is  taken,  a  state  of  stupor  follows, 
and  death  has  been  known  to  result  in  some  cases.  Between 
these  two  extremes  there  may  be  a  variety  of  manifestations. 
As  a  stimulant,  it  appears  to  many  to  have  a  kindly  action,  to 
cause  a  glow  and  sense  of  warmth,  to  increase  muscular  activity, 
and  to  make  the  mind  and  organs  of  speech  more  nimble. 

17.  Alcohol  and  Crime.  —  "Thirty  years  of  judicial  experience  have 
taught  me  that  of  the  crimes  which  judges  are  called  upon  to  try,  and 
upon  which  sentences  of  the  law  are  pronounced,  more  f,han  eight-tenths 
of  them  involving  any  degree  of  violence  in  their  character  are  directly 
traceable  to  the  liquor  shops.  How  often  have  I  had  young  men  look  up 
at  me  when  I  asked  them  what  they  had  to  say  why  the  sentence  of  the 
law  should  not  be  pronounced,  and  declare,  'I  should  never  have  done  this 
crime  if  it  were  not  for  drink.  Rum  was  my  ruin  ;  rum  struck  the  blow, 
and  not  my  hand,  that  killed  the  man  for  whose  death  I  am  tried ;  rum 
has  caused  me  to  beat  my  wife,  and  injure  my  helpless  child,  and  to  do 
the  act  which  now  confines  me  to  a  prison."  —  Judge  Noah  Davis. 

*  "  Suppose,  for  instance,  you  measure  your  muscular  strength  with  a 
*  health  lift '  or  dynamometer  (by  which  muscular  exertion  can  be  accu- 
rately measured),  and  then  take  some  of  the  drink  in  the  strength- 
inspiring  power  of  which  you  have  most  confidence,  and  when  you  are 
most  exhilarated  by  it,  and  feel  as  if  you  could  shoulder  a  large  fragment 
of  Mount  Olympus,  measure  your  strength  again.  The  drink  has  fooled 
you,  that  is  all.  You  felt  that  you  were  stronger  than  natural ;  you  find 
that  the  narcotic  has  been  true  to  its  paralyzing  nature,  and  that  you  are 
weaker.  Then,  after  a  time,  when  the  drug  has  spent  itself,  and  reaction 
(so  called)  comes  on,  and  you  feel  weak  and  prostrated,  measure  your 
strength  once  more.  Fooled  again;  the  stuff  has  fooled  you  twice. 
When  you  felt  yourself  strong  you  were  weak,  and  now  when  you  feel 
yourself  weak,  you  find  yourself  stronger  —  your  natural  strength  is 
returning,  and  what  you  have  called  reaction  is  in  reality  recovery  from 
the  weakening  effects  of  the  narcotic."  — Dr.  A.  F.  Kinne. 


69.  Poisonous  effects  of  alcohol  f 


THE  NERVOUS  8TSTEM  255 

70.  Chronic  Alcoholism  and  Delirium  Tremens.  —  When  per- 
sons become  habituated  to  the  over-indulgence  of  alcohol  in 
large   quantities,  its   effects   produce  serious  and  permanent 
changes  in  the  general  nervous  system,  the  various  manifes- 
tations of  which  are  spoken  of  as  chronic  alcoholism.     They 
manifest   themselves   chiefly  in  a  disturbance  of  the  various 
brain  functions.     These  persons  usually  suffer  from  sluggish 
brain  action,  and  a  serious  disturbance  of  many  of  the  brain 
functions,  such,  for  instance,  as  loss  of  memory.      There  is 
usually  present  trembling  of  the  hands,  trembling  of  groups  of 
muscles  in  other  parts  of  the  body;  and  they  are  unable  to 
endure  any  bodily  fatigue.  •  When  a  person  has  been  consum- 
ing large  quantities  of  alcohol  for  some  time,  a  sudden  and 
very  violent  delirium  may  result.     To  this  has  been  given  the 
name  of  delirium  tremens,  from  the  fact  that  it  is  accompanied 
by  more  or  less  violent  trembling  of  the  entire  body.     It  is 
extremely  dangerous   to  life,  often  producing  death,  and  in 
many  instances  insanity. 

71.  Tobacco  and  its  Effects.  —  Tobacco,  familiarly  known  as 
"the  weed,"  is  an  annual  plant  said  to  be  a  native  of  America. 
It  grows  to  a  height  of  several  feet,  with  leaves  of  a  pale  green 
color.    These  leaves,  when  dried,  are  made  into  cigars,  chewing 

18.  "  Here  is  a  company  of  'jolly  good  fellows,'  all  standing  on  their 
feet,  their  faces  red  and  radiant,  and  all  swinging  their  arms  and  talking 
at  once.  These  men  have  been  taking  alcohol,  and,  surely,  you  will  say, 
it  has  stimulated  them.  But  if  you  will  attend  for  a  moment  to  what 
they  are  saying,  you  will  see  that  there  is  no  true  brain-stimulation  about 
it.  We  shall  be  reminded  rather  of  what  Addison  says  of  the  difference 
between  the  mind  of  the  wise  man  and  that  of  the  fool :  There  are  infi- 
nite, numberless  extravagancies,  and  a  succession  of  vanities  which  pass, 
through  both.  The  great  difference  is  that  the  first  knows  how  to  pick 
and  cull  his  thoughts  for  conversation,  by  suppressing  some  and  com- 
municating others ;  whereas  the  other  lets  them  all  indifferently  fly  out 
in  words.'  The  case  with  these  revelers  is  precisely  this.  The  poison 
which  they  have  taken  has  paralyzed  their  conservative  faculties,  and  the 
talking  propensity  is  running  on  without  anything  to  hold  it  in  check  and 
regulate  it."  — Dr.  A.  F.  Kinne. 


TO.  Describe  the  tobacco  plant. 

tt.  What  ia  its  effect  upon  the  nerves  f 


256  THE  NERVOUS  SYSTEM 

and  smoking  tobacco,  and  snuff,  which  are  extensively  used 
throughout  the  civilized  world 

72.  Tobacco  as  a  Poison.  —  Tobacco  is  a  poison  to  the  young, 
and  is  far  more  hurtful  to  the  adult  than  is  generally  supposed, 
It  may  be  stated,  as  a  rule,  that  there  are  few  persons  who  use 
it  habitually  that  do  not  suffer  injury  from  it.     The  injury  is 
mainly  caused  by  what  is  known  as  "  nicotine,"  one  of  the  nar- 
cotic poisons,  and  particularly  prominent  in  tobacco.     Some  of 
the  effects  of  its  limited  use  are  nausea,  vomiting,  vertigo,  and 
weakness ;  and  its  prolonged  use,  by  those  who  are  sensitive 
to  it,  often  results  in  convulsions  and  other  like  symptoms, 
together  with  an  irritability^  and  weakened  condition  of  the 
heart,  known  to  physicians  as  the  "tobacco-heart." 

73.  Effects  on  the  Young.  —  Of  the  pernicious  influence  of 
the  use  of  tobacco  upon  the  young,  the  testimony  of  the  Naval 
and  Military  Academies  of  the  country  is  very  decided.     It 
has  at  times  been  allowed  in  both  institutions,  but  at  present 
it  is  forbidden,  on  the  ground  that  its  use  is  attended  with 
serious  damage  to  health.      It  is  stated  that  its  prohibition 
at  the  Naval  Academy  in  1881  was  received  with  unanimous 
approval  by  the  officers  in  charge,  and  with  "great  joy  by 
many  of  the  cadets."     Tremor  of  the  muscles,  caused  by  smok- 
ing, was  very  noticeable  in  the  drawings  that  form  so  impor- 
tant a  part  of  the  cadets'  work.      A  teacher  of  drawing  of 
fourteen  years'  experience  has  said  that  he  can  always  tell 
from  the  character  of  the  lines  in  the  drawings,  whether  or 
not  the  pupils  use  tobacco.     Its  avoidance  has  resulted  in  the 
reduced  number  of  minor  ailments  that  swelled  the  sick-list  in 
years  when  its  use  was  unrestricted.     Athletes  and  other  per- 
sons who  engage  in  running  matches  and  the  like,  are  com- 
monly not  allowed  to  use  either  alcohol  or  tobacco  while  they 
are  "  in  training  " ;  their  use  interferes  with  the  fullest  devel- 
opment of  muscular  strength.     (Read  Note  19.) 

19.  "  The  end  of  all  science  is  to  secure  long  life  and  good  health  to 
the  individual  arid  the  race,  and  it  ought  to  be  a  part  of  the  rational 
creed  of  every  good  man  and  woman  to  abjure  the  use  of  tobacco,  and 
keep  others  from  falling  into  the  vice." — Dr.  C.  E.  Drysdale. 

"  Tobacco  is  certainly  not  a  food  for  man,  nor  has  it  much  value  as  a 

72.  Tobacco  as  a  poison  ?    73.  The  effects  of  tobacco  on  the  young  f 


THE  NERVOUS  SYSTEM  257 

74.  Cigarette-Smoking.  —  This  form  of  taking  tobacco  is  in- 
jurious in  two  particulars  that  do  not  apply  to  the  other  forms. 
The  smoker  of  cigarettes,  either  voluntarily  or  involuntarily, 
takes  into  his  lungs  a  very  large  amount  of  smoke,  and  with 
it  that  hurtful  element,  carbonic  oxide.     Again,  there  is  an 
excessive  amount  of  adulteration  of  the  tobacco  in  cigarettes ; 
and  one  substance,  opium,  is  largely  so  used,  and  is  extremely 
injurious. 

75.  Snuff-Taking.  —  In   addition   to  the   hurtful   effects  of 
tobacco  generally,  snuff-taking  is  notoriously  injurious  to  the 
senses  of  smell  and  taste,  and  to  the  voice. 

76.  Narcotics.  —  The  term  narcotic  is  applied  to  different 
substances  derived  chiefly  from  the  vegetable  kingdom,  which 
have  the  wonderful  property  of  quieting  pain  and  causing 
sleep.    Next  in  importance  to  alcohol,  which  belongs  to  the 
narcotics,  are  opium  (and  its  preparations),  chloral  hydrate, 
hasheesh,  and  chloroform. 

77.  Opium. — Opium  is  the  thickened  juice  of  the  poppy- 
plant  of  India,  and  is  commonly  regarded  as  the  most  impor- 
tant of  the  narcotics.     Its  active  principle  is  morphine,  which 
gives  the  soothing  property  to  laudanum,  paregoric,  and  Dover's 
powders.     It  is  also  used  in  nostrums  to  put  infants  t9  sleep : 
but,  unwisely  used,  often  brings  on  a  sleep  that  knows  no 
waking. 

78.  Effects  of  Opium.  —  Opium  is  particularly  injurious  to 
the  young,  even  small  doses  sometimes  producing  alarming 
symptoms.     Upon  adults  the  external  effects  are  not  as  notice- 
medicine.    The  tobacco-worm  is  the  only  animal  known  to  thrive  upon 
it."  — JP.  H.  Hamilton. 

"An  illustration  of  the  depressing  influence  of  tobacco  is  given  by 
Dr.  Jacob  Bigelow,  who  states  that  soldiers,  when  wishing  to  shirk  duty 
and  get  on  the  sick-list,  sometimes  succeed  in  bringing  on  the  symptoms  of 
alarming  sickness  by  wearing  a  piece  of  tobacco  under  each  armpit.  The 
skin  absorbs  sufficient  of  the  poison  to  affect  the  system  to  a  marked 
degree."  

74.  What  Is  said  of  cigarette-smoking  ?  77.  What  is  opium  ? 

75.  Snuff-taking  ?  78.   What  are  the  effects  of  using  opium  ? 

76.  What  do  you  understand  by  narcotics  ? 


258  THE  NERVOUS  SYSTEM 

able  as  are  those  of  alcohol,  but  the  mind  is  more  deeply  stirred 
and  the  flow  of  ideas  more  copious. 

79.  Danger  from  Opiates.  —  The  use  of  opium  for  relieving 
pain  has  been  known  for  hundreds  of  years.     The  enchanting 
sense  of  relief  to  suffering  wrought  by  opiates  leads  to  the  mor- 
phine habit,  commonly  called  opium-eating.     It  will  be  seen, 
therefore,  why  such  great  care  is  exercised  by  physicians  in 
administering  opiates,  lest  their  patients  afterward  fall  into  the 
habit  of  taking  them  without  medical  advice.     (Bead  Note  20.) 

80.  Physiological  Effects  of  Opium. — The  frequent  use  of 
opium  disturbs  and  weakens  the  stomach  as  well  as  the  other 
digestive  organs ;  hence  we  invariably  find  the  opium-eater  to 
be  a  lean,  yellow,  sallow  person.     His  muscular  and  mental 
powers  are  impaired,  and  his  will  is  terribly  enfeebled.     This 
dreadful  habit  can  be  broken  only  with  unspeakable  suffering 
to  its  victim. 

81.  Chloral   Hydrate.  —  Chloral   hydrate,   commonly  called 
chloral,  is  produced  from  alcohol ;  but  its  power  as  a  sedative 
was  not  generally  known  until  within  the  past  twenty  years. 
It  also  is  a  destroyer  of  appetite  as  well  as  of  digestion,  unless 
prescribed  in  proper  doses,  and  the  unfortunates  once  given 
over  to  it  find  themselves  unable  to  sleep  without  its  continued 
use.     It  should  never  be  taken  except  under  the  direction  of  a 
physician. 

20.  "The  opium-eater  loses  none  of  his  moral  sensibilities  or  aspira- 
tions ;  he  wishes  and  longs  as  earnestly  as  ever  to  realize  what  he  believes 
possible,  and  feels  to  be  exacted  by  duty  ;  but  his  intellectual  apprehen- 
sion of  what  is  possible  infinitely  outruns  his  power,  not  of  execution 
only,  but  even  the  power  to  attempt.  He  lies  under  the  weight  of  incu- 
bus and  nightmare ;  he  lies  in  sight  of  all  that  he  would  fain  perform, 
just  as  a  man  forcibly  confined  to  his  bed  by  the  mortal  languor  of  a 
relaxing  disease,  who  is  compelled  to  witness  injury  and  outrage  offered 
to  some  object  of  his  tenderest  love ;  he  curses  the  spells  which  chain 
him  down  from  motion ;  he  would  lay  down  his  life  if  he  might  but  get 
up  and  walk  ;  but  he  is  powerless  as  an  infant,  and  cannot  even  attempt 
to  rise."  —  De  Quincey's  Confessions  of  an  Opium-Eater. 


79.  What  the  danger  ? 

80.  What  effect  upon  the  system  ? 

81.  What  do  you  know  of  chloral  hydrate  ? 


THE  NERVOUS  SYSTEM  259 

82.  Hasheesh.  —  Hasheesh,  the  juice  of  Indian  hemp,  is  said 
to  be  used  by  millions  of  the  inhabitants  of  Asia.     It  is  not 
known  much  in  the  western  countries.    In  the  East  the  excite- 
ment caused  by  its  use  takes  the  form  of  furious  madness,  lead- 
ing its  victim  to  commit  acts  of  violence  and  murder.     Hence 
the  term  "  hasheeshers  "  in  our  language  has  come  to  be  synony- 
mous with  assassins.     (Bead  Note  21.) 

83.  Cocaine.  —  Cocaine  is  a   drug,  derived   from   the  Coca 
plant,  a  native  of  Peru,  South  America.     Its  use  in  medicine 
is  —  like  many  of  the  dangerous  drugs  —  of  great  value.     By 
injection   under  the   skin,  we   can  render  parts  of  %  the  body 
entirely  insensitive  to  pain,  so  that  quite  extensive  operations 
may  be  undertaken  without  producing  any  pain.     It  is  used 
also  in  operations  upon  the  eye,  mouth,  and  nose,  where  it  pro- 
duces its  effect  when  a  solution  of  it  is  dropped  on  the  surface. 
Because  of  its  powerful  effect  in  relieving  pain,  many  persons 
have  become  addicted  to  its  use.     In  many  it  also  produces 
pleasurable   sensations,   to  repeat  which,  they  have   to  take 
larger  and  larger  doses,  and  very  soon  become  slaves  to  its 
use.     It  rapidly  undermines  the  general  health,  and  soon  leads 
to  death  if  its  use  is  not  speedily  checked. 

84.  Chloroform.  —  Chloroform,  another  product  from  alcohol, 
is  used  by  inhalation  when  surgical  operations  are  to  be  per- 
formed.    As  it  is  very  powerful  and  subtile  in  its  action,  the 
unskilful  use  of  it  is  dangerous  in  the  extreme.     The  habit  of 
taking  chloroform  by  those  who  are  great  physical  sufferers,  or 
whose  constitutions  have  been  wrecked  by  the  use  of  other 
narcotics,  should  be  discouraged.     It  too  often  happens  that 
the  career  of  such  is  short,  for  the  drug  may  easily  be  taken 
in  excess  and  so  cause  death. 

21.  "As  everybody  knows,  the  intoxication  caused  by  alcoholic  liquors, 
by  hasheesh,  by  opium,  after  a  first  period  of  excitement,  brings  about  a 
notable  impairment  of  the  will.  The  individual  is  more  or  less  con- 
scious of  this  ;  other  persons  see  it  more  clearly.  Soon  —  especially  under 
the  influence  of  alcohol  —  the  weakening  of  the  will  becomes  excessive. 
The  extravagances,  violences,  and  crimes  committed  in  this  state  are 
innumerable."  —  Dr.  T.  Eibot. 


82.  What  is  hasheesh  ?    Its  use?    88.  Cocaine?    Its  use?    84.  Chloroform?    Its  use? 


260  THE  NERVOUS  SYSTEM 

85.  Sleep  Produced  by  Narcotics.  —  Opium  and  the  opiates 
have  the  power  of  quieting  the  activity  of  the  brain,  and  of 
compelling  sleep.     This  may  be  a  blessed  action  if  skilfully 
applied  by  the  physician,  but  not  so  applied  it  is  the  source  of 
infinite  peril.    The  sleep  so  caused  differs  from*natural,  restful 
slumber,  especially  in  the  fact  that  the  'after-effects  are  com- 
monly depressing  and  disturbing  to  the  brain  to  the  extent  of 
being  harder  to  bear  than  the  wakef ulness  on  account  of  which 
the   drugs   are   taken.      Very   young    persons   are   especially 
subject  to  injury  by   sleep-producing  medicines;   and   many 
are  the  deaths  that  have  been  caused  among  infants  by  the 
giving  of    " soothing    syrups,"    "cordials,"   and   "anodynes," 
that  are  so  freely  sold  for  the  purpose  of  compelling  sleep. 

86.  Results  of  the  Use  of  Narcotics.  —  The  use   of  any  of 

these  narcotics,  without  proper  medical  advice,  is  their  abuse. 
In  this  way  they  become  powerful  for  harm.  They  are  no 
longer  remedies,  but  poisons.  Self-prescribed,  they  have  a 
thousand  times  been  the  instrument  of  unintentional  suicide. 

87.  The  craving  for  narcotics  is  found  in  many  nervous  people, 
or  in  those  whose  general  health  is  not  good.     They  experience 
such  a  great  relief  from  the  use  of  narcotics,  in  simple  ner- 
vousness, in  pain,  or  in  insomnia,  that  they  naturally  wish  to 
repeat  these  pleasant  experiences.     This  desire  soon  develops 
into  a  craving  like  as  that  of  the  drunkard  for  his  alcohol. 
Such  a  person  should  place  himself  under  the  care  of  a  phy- 
sician. 

88.  Effects  of  Heredity.  —  There  seems  to  exist  in  a  number 
of  people  a  natural  desire  for  alcohol,  or  for  any  one  of  the 
drugs  and  narcotics  enumerated  above.     Upon  inquiry,  it  will 
often  be  found  that  their  parents  or  grandparents  had  similar 
tastes,  and  we  therefore  speak  of  them  as  having  hereditary 
tastes   or   desires.     Persons  who  discover  in  themselves  this 
hereditary  liking  for  either  alcohol  or  drugs  should  never  use 
either  of  them,  for  fear  of  becoming  addicted  to  their  use. 

85.  Sleep  produced  by  narcotics  ?    Danger  of  using  "  soothing  syrups,"  etc.  ? 

86.  Self-prescribed  narcotics  ? 

87.  The  craving  for  narcotics  ? 
83.  Effects  of  heredity? 


THE  NERVOUS  SYSTEM 


261 


TOPICAL  OUTLINE 


Pia  mater 


Coverings  J  Arachnoid 


Dura  mater 


Cerebrum 


Structure 


Functions 


NERVOUS 
SYSTEM  . 


NERVE  SUB- 
STANCE .  .  . 

NERVE 
FIBRES    .  .  . 


NERVES 


Cerebellum 


Medulla  . 


Cerebrum 


Cerebellum 


Medulla 


Cerebro- 
spinal  . 


Sympathetic 


f  Cellular  .  .  , 
'  Fibrous  .  . 

Fresh 
After  death 

f  Afferent .  . 

<  Efferent  .  . 
[Mixed.  .  . 


f  Inner,  delicate,  vascular. 
-I  Closely  invests  the  brain. 
[  Follows  all  the  convolutions. 

A  serous  membrane. 
f  Tough,  fibrous. 
J  Outer  surface  rough,  and  in  contact  with  the 

skull. 

I  Inner  surface  smooth. 
f  Right  and  left  hemispheres. 
J  Surface  convoluted. 
1  Fills  all  upper  portion  of  cranium. 
I  Gray  matter  outside. 

Right  and  left  hemispheres. 

Surface  drawn  into  folds. 

Fills  occipital  portion  of  cranium. 

Gray  matter  outside. 
>  Connects  the  brain  with  the  cord. 
'  Gray  matter  inside. 
(  Chief  seat  of  sensation. 
-!  The  organ  of  the  will  and  voluntary  motion. 
[  The  seat  of  the  intelligence. 
i  The  seat  of  muscular  sense. 

<  Co-ordinates  muscular  movements. 

(Governs  the  muscles  of  respiration  and  deglu- 
tition. 
A  conducting  medium  between  the  brain  and 
the  cord. 

.  |  Brain  and  its  nerves, 
f  Conslsts  Of  1  Spinal  cord  and  its  nerves. 
i  Organs  of  sense. 
L  Fibres  distributed  to  ,  Voluntary  muscles. 

Double  chain  of  ganglia,  on 
each  side  of  the  vertebral 
column. 

Various  disconnected  ganglia. 
f  The  internal  organs. 

Fibres  distributed  to  -j  The  walls  of   blood- 
[     vessels. 

Grayish  —  in  nerve  centres. 
(  Nerve  fibres — forms  nerves,  and  enters  into 

<  the  structure  of  nerve  centres. 

A  simple  semitransparent  filament. 
j  A   tube,    containing   a  white   opaque   sub- 
*      stance. 

(  Convey  impressions  to  a  centre  only. 
"l  Also  called  sensory  nerves, 
f  Convey  impressions  from  a  centre  only. 
;  Fibres  terminate  in  muscular  fibres 
t  Also  called  motor  nerves. 

Contain  both  afferent  and  efferent  fibres. 


Consists  of 


262 


•THE  NERVOUS  SYSTEM 


THE  SPINAL 
CORD    . 


Reflex  action 


Position 


Coats 


Structure 


i  In  the  spinal  canal  formed  by  the  vertebral 
I      column. 
f  About  eighteen  inches. 
Length    .  j  Extends  from  the  medulla  oblongata  to  the  first 

L     lumbar  vertebra. 
Thickness      About  one-third  of  an  inch. 

Pia  mater — delicate,  vascular. 

Arachnoid — serous,  forming  a  loose  bag. 

Dura  mater — tough,  fibrous. 

(A  layer  of  fatty  tissue  lies  between  the  dura 

mater  and  the  bony  canal.) 
Gray  matter  internal. 
White  matter  external. 
Anterior  fissure. 

Posterior  fissure  —  deeper  and  narrower. 
Central  canal  —  microscopic, 
f  Thirty-one  pairs  — between  the  vertebrae. 
I  Crowded  at  the  lower  extremity  of  the  cord  — 
Nerves .  .  J\      cauda  equina. 

Each  trunk  formed  by  the  union  of  two  roots. 

.    (  Anterior  —  motor. 
•Ro°ts1  Posterior -sensory. 
f  Conduction  of  impressions. 
I  A  centre  for  reflex  action  (gray  matter). 
j  Sensory  fibres  —  cross  as  they  enter  the  cord. 
I  Motor  fibres  —  cross  in  the  medulla  oblongata. 
f  A  disturbed  condition  of  sensory  fibres —  » 

j  Conducted  to  a  nerve  centre  — 
{  Reflected  by  the  nerve  centre  along  motor  fibres  to  their 

terminations  in  muscles  — 
I  Muscular  contraction. 


Functions 


QUESTIONS  FOR  TOPICAL  REVIEW       • 

PAGE 

1.  State  fully  what  is  meant  by  the  term  vegetative  function 217 

2.  To  what  does  man  owe  his  position  as  the  head  of  the  animal  creation  ?      218 

3.  What  can  you  state  on  the  subject  of  special  organs  for  separate 

functions  ? 219 

4.  Describe,  as  fully  as  you  can,  the  structure  of  the  nervous  system.  218,  219 

5.  Describe  the  brain,  its  location,  size,  shape,  and  structure 219-222 

6.  Describe  the  brain  proper,  or  cerebrum 222,  223 

7.  Describe  the  little  brain,  or  cerebellum 224,  225 

8.  Describe  the  spinal  cord  227,  228 

9.  What  are  the  spinal  nerves,  and  how  are  they  arranged  ? 228 

10.  What  is  the  character  and  substance  of  their  tissues  ? 228,  229 

11.  State  and  illustrate  how  the  nerve-fibres  perform  their  office 229,  230 

12.  Describe  the  sympathetic  system  of  nerves 230,  231 

13.  State  the  properties  of  nervous  tissue,  and  illustrate 231-233 

14.  Explain  the  functions  of  the  nerves 233 

15.  What  is  meant  by  transient  paralysis  of  a  nerve  ?    Illustrate 234,  235 

16.  What  can  you  state  of  the  rate  of  message-motion  along  a  nerve?. .      235 


THE  NERVOUS  SYSTEM  2G3 


PAGE 

17.  What  are  the  functions  of  the  spinal  cord  ? 236 

18.  State  what  you  can  of  the  form  of  paralysis  known  as  paraplegia. .      236 

19.  What  experiments,  with  results,  upon  the  spinal  cord  are  noted?.  236,  237 

20.  Give  the  direction  of  fibres  of  cord 237,  238 

21.  How  does  the  left  side  of  brain  feel  pain  in  right  hand  ? 238 

22.  What  is  understood  by  the  reflex  action  of  the  cord  ? 238 

23.  What  experiments  are  mentioned  to  prove  this  power  of  the  cord  ?  238-240 

24.  What  are  the  uses  of  the  reflex  action  of  the  cord  ? 240-243 

25.  What  is  the  medulla  oblongata  and  its  function  ? 243,  244 

26.  What  can  you  state  of  the  functions  of  the  cranial  ganglia  ? 245 

27.  What  are  the  functions  of  the  cerebellum  ? 245 

28.  What  is  the  function  of  the  cerebrum  ? 245 

29.  In  what  way  does  the  size  of  the  brain  generally  indicate  the 

character? 246 

30.  What  facts  show  that  the  gray  substance  of  the  brain  is  insensi- 

tive ? 246,  247 

31.  Upon  what  does  the  faculty  of  language  seem  to  depend  ? 248 

32.  Of  what  importance  is  the  reflex  action  of  the  brain  ? 249 

33.  In  what  ways  is  this  importance  made  manifest  ? 250 

.'U.   Give  the  effects  of  alcohol  upon  the  brain 251 

35.  How  does  it  affect  the  mind  ? 252 

36.  What  is  said  of  the  effect  upon  the  will  ? 252 

37.  How  is  the  whole  system  affected  ? 254,  255 

38.  What  is  said  of  tobacco ? .,...  255-257 

39.  Define  and  illustrate  the  term  narcotic 257 

40.  Give'  the  statement  regarding  opium 257 

41.  State  what  you  can  of  chloral 258 

42.  What  is  hasheesh  and  its  effect  ? 259 

43.  What  is  said  of  chloroform  ? 259 

44.  Give  general  results  of  use  of  narcotics 260 


CHAPTER  X 

THE  SPECIAL  SENSES 

The  Production  of  Sensations  —  Variety  of  Sensations  —  General  Sensi- 
bility —  Pain  and  its  Function  —  Special  Sensation,  Touch,  Taste, 
Smell,  Sight,  and  Hearing  —  The.  Hand, -the  Organ  of  Touch — The 
Sense  of  Touch  —  Delicacy  of  Touch  —  Sensation  of  Temperature  and 
Weight — The  Tongue,  the  Organ  of  Taste—  The  Nerves  of  Taste  — 
The  Sense' of  Taste  and  its  Relations  with  the  other  Senses —  The 
Influence  of  Education  on  the  Taste  —  The  Nasal  Cavities,  or  the 
Organs  of  Smell  —  The  Olfactory  Nerve  —  The  Uses  of  the  Sense  of 
Smell  — The  Sense  of  Sight— Light  — The  Optic  Nerve— The  Eye- 
ball and  its  Coverings —  The  Function  of  the  Iris —  The  Sclerotic, 
Choroid,  and  Retina — The  Tears  and  their  Function — The  Move- 
ments of  the  Eyeball —  The  Function  of  Accommodation —  The  Sense 
of  Hearing  and  Sound —  The  Ear,  or  the  Organ  of  Hearing —  The 
External,  Middle,  and  Internal  Ear 

1.  Production  of  Sensations.  —  We  have,  already  seen  that  the 
true  centre  of  sensation  is  some  organ  within  the  skull,  proba- 
bly among  the  gray  masses  at  the  base  of  the  brain ;  but  the 
mind  never  perceives  impressions  at'  that  point ;  on  the  con- 
trary, it  always  refers  them  to  the  external  organs  of  sensa- 
tion.    Hence,  it  is  convenient  to  say  that  those  outer  parts 
possess  the  property  of  sensibility.     For  instance,  we  say  that 
we  hear  with  the  ear,  taste  with  the  tongue,  and  feel  with  the 
ringers.     That  this  is  not  the  exact  truth  is  proved  by  the  fact 
that,  whenever  the  nerve  connecting  one  of  these  organs  with 
the  brain  is  severed,  it  at  once  loses  its  capacity  for  sensation. 

2.  Consciousness,  another  faculty  of  the  brain,  is  necessary 
to  complete  a  sensation.     During  sleep,  and  in  other  uncon- 


1.  True  centre  of  sensation  ?    Place  of  the  mind's  impressions  ?    What  is  it  convenient 
to  say  ?    What  further  is  stated  ? 

2.  Consciousness  ?    During  sleep  ?    In  profound  Insensibility  ? 


THE  SPECIAL  SENSES  265 

scious  states,  the  usual  impressions  are  presented  to  the  ear, 
the  nose,  and  the  skin;  but  they  fail  to  excite  sensations, 
.because  the  nerve-centres  are  inactive.  In  profound  insensi- 
bility, from  chloroform  or  ether,  a  limb  may  be  removed  with- 
out occasioning  the  least  feeling. 

3.  Variety  of  Sensations.  —  All  animals  have  some  degree  of 
sensibility.     It  is,  of  course,  feeble  and  indistinct  in  the  lower 
forms  of  life,  but  increases  in  power  and  variety  as  we  ascend 
J;he  scale.     In   the  earth-worm,  the.  nervous   system   is   very 
simple,  the  sensibility  being  moderate  and  alike  in  all  parts; 
hence,  if  its  body  be  cut  into  two  pieces,  each  piece  will  have 
the  same  degree  of  feeling  as  before.     As  we  approach  man, 
however,  the  sensations  multiply  and  become  more  acute;  the 
organs  are  more  complex,  and  special  parts  are  endowed  with 
special  gifts.     These  special  organs  cannot  be  separated  from 
the  rest  of  the  body  without  the  loss  of  the  functions  they  are 
designed  to  exercise. 

4.  The  lowest  form  of  sensation  —  that  of  simple  contact  — 
is  possessed  by  the  lowest  of  the  animal  creation.     The  highest 
forms  are  those  by  which  we  are  enabled  to  know  the  proper- 
ties of  external  objects,  such  as  shape,  size,  sound,  and  color. 
A  variety  of  means  of  communicating  with  the  outer  world  is 
the  necessary  possession  of  a  high  intelligence.     Sensations  are 
modified  by  use.     They  become  more  acute  and  powerful  by 
moderate  exercise,  or  they  are  dulled  by  undue  excitement. 
The  former  is  shown  by  the  acute  hearing  of  the  Indian,  by  the 
sharp  sight  of  the  sailor,  and  by  the  delicate  touch  of  the 
blind.     The  latter  is  exemplified  by  the  impaired  hearing  of 
the  boiler-maker,  and  the  depraved  taste   of  him  who  uses 
pungent  condiments  with  his  food.     Again,  impressions  habitu- 
ally presented  may  not  be  consciously  felt,  as  is  the  case  with 
the  rumbling  of  carriages  in  a  neighboring  street,  or  the  regular 
ticking  of  a  clock.     All  sensations  become  less  vivid  with  the 
advance  of  age,  especially  hearing  and  vision. 

8.  Sensibility  in  animals  ?    In  the  earth-worm  ?    In  man  f 

4.  The  lowest  form  of  sensation  ?     The  highest  ?    Sensations,  how  modified  ?    What 
farther  can  you  state  as  to  habitual  impressions  ? 


266  THE  SPECIAL  SENSES 

5.  General  Sensibility.  —  There  is  a  property  possessed  by 
nearly  all  parts  of  the  human  body  which  we  call  general 
sensibility.     We  have  recently  seen  that  the  brain  is  wholly 
insensitive,  and  may  be  cut  or  pinched  without  pain.     The 
same  is  true  of  the  nails,  hair,  the  scarf-skin  or  external  cover- 
ing of  the  body,  and  a  few  other  structures.     In  these  parts  no 
nerves  are  found.     On  the  other  hand,  the  sensibility  of  the 
true  skin,  and  of  mucous  membranes,  as  of  the  eye  and  nose,  is 
exquisite,  these1  organs  having  a  large  supply  of  sensory  nerve- 
fibres.     The  bones  and  tendons  have  less  of  these  fibres,  and 
are  only  moderately  sensitive. 

6.  The  sensibility  of  any  part  of  the  body,  then,  depends 
upon  the  number  of  nerves  present ;  and,  as  a  rule,  the  nervous 
supply  is  proportional  to  the  importance  of  the  part,  and  to  its 
liability  to  injury.     When,  therefore,  a  surgical  operation  is 
performed,  the  most  painful  part  of  it  is  the  incision  through 
the  skin — the  muscles,  cartilage,  and  bone  being  comparatively 
without  sensation.     Hence,  if  we  could  benumb  the  surface, 
certain  of  the  lesser  operations  might  be  undergone  without 
great  inconvenience.     This  is,  in  fact,  very  successfully  accom- 
plished by  means  of  the  cold  produced  by  throwing  a  spray  of 
ether,  or  of  some  other  rapidly  evaporating  liquid  upon  the 
part  to  be  cut. 

7.  Tickling  is  a  modification  of  general  sensibility.     At  first 
it  excites  a  pleasurable  sensation,  but  this  soon  passes  into 
pain.     It  is  only  present  in  those  parts  where  the  sense  of 
touch  is  feeble.     But  all  impressions  are  not  received  from 
without ;  'there  are,  also,  certain  internal  sensations,  as  they  are 
called,  which  depend  upon  the  condition  of  the  internal  organs, 
such  as  appetite,  hunger,  thirst,  dizziness  when  looking  down 
from  some  lofty  position,  drowsiness,  fatigue,  and  other  feel- 
ings of  comfort  or  discomfort.     General  sensibility,  whether  of 
the  internal  or  external  organs  of  the  body,  chiefly  depends 

5.  General  sensibility  ?    What  have  we  seen  as  regards  the  brain  ?    Of  what  other 
structures  is  the  same  true  ? 

6.  The  cause  of  sensibility  ?    Painful  part  in  a  surgical  operation  ?    Benumbing  the 
surface  ?    How  done  by  ether  ? 

7.  Tickling?    Internal  sensations  ?    The  nerves  of  general  sensibility  ? 


THE  SPECIAL  SENSES  267 

upon  the  sensory  fibres  of  the  spinal  nerve.  The  face,  how- 
ever, is  supplied  by  the  sensory  cranial  nerves.  The  sympa- 
thetic system  has  a  low  grade  of  feeling  in  health,  but  disease 
in  the  parts  served  by  it  arouses  an  intense  degree  of  pain. 

8.  The  Sensation  of  Pain. — What  then  is  pain?    Is  it  iden- 
tical  with  ordinary   sensibility  ?     There   seems   to   be   some 
necessary  connection  between  the  two  feelings,  for  they  take 
place  through  the  same  channels,  and  they  are  alike  intense  in 
the  same  situations.     But  sensibility  habitually  contributes  to 
our  sources  of  pleasure  —  the  very  opposite  of  pain ;  hence, 
these  feelings  cannot  be  identical. 

9.  Pain  must,  therefore,  "be  a  modification  of  the  general 
sensibility  which  follows  an  excessive  degree  of  excitement  of 
the  nerves,  there  being  a  natural  limit  to  the  amount  of  stimu- 
lation which  they  will  sustain.    So  long  as  this  limit  is  observed, 
the  part  excited  may  be  said  to  be  simply  sensitive  ;  but  when 
it  is  exceeded,  the  impression  becomes  painful.    This  difference 
between  sensibility  and  pain  is  well  shown  by  the  effects  of 
sunlight  upon  the  eye.     The  indirect  illumination  of  the  sun 
arouses  only  the  former  feeling,  and  is  indispensable  to  our 
comfort  and  existence,  while  the  direct  ray  received  into  the 
eye  occasions  great  pain. 

10.  The  Uses  of  Pain. — The  dread  of  pain  is  a  valuable 
monitor  to  the  body.     It  puts  us  on  our  guard  in  the  presence 
of  danger,  teaches  moderation  in  the  use  of  our  powers,  indi- 
cates the  approach  of  disease,  and  calls  attention  to  it  when 
present.     The  word  disease,  in  fact,  according  to  its  original 
use,  had  reference  simply  to  the  pain,  or  want  of  ease,  which 
commonly  attends  disordered  health.     When  we  observe  the 
serious  mishaps  which  occur  when  sensibility  and  pain  are 
absent,  we  cannot  fail  to  appreciate  its  value.     For  example,  a 
paralytic,  in  taking  a  foot-bath,  forgets  to  test  its  temperature, 
and  putting  his  limbs  into  water  while  it  is  too  hot,  is  severely 
scalded  without  knowing  it. 

8.  Connection  between  pain  and  sensibility  ? 

9.  Explain  the  difference  between  pain  and  sensibility. 

10.  Dread  of  pain  ?    How  may  its  value  be  appreciated  ?    Example  ? 


268  THE  SPECIAL  SENSES 

11.  A  traveler,  overcome  by  cold  and  fatigue,  lies  down  and 
falls  asleep  near  a  large  fire,  and  when  he  is  aroused  in  the 
morning,  it  is  discovered  that  one  of  his  feet  has  been  insen- 
sibly destroyed.     A  grain  of  sand,  lodging  in  an  insensitive 
eye,  may  cause  inflammation,  ancl  even  the  loss  of  sight.     If 
intense  light  were  not  painful  to  the  eye,  many  a  child  would 
innocently  gaze  upon  the  glories  of  the  sun  to  the  ruin  of  his 
sight. 

12.  Pain  is,  indeed,  a  present  evil,  but  its  relations  with  the 
future  prove  its  mission  merciful.     Painful  impressions  cannot 
be  recollected  from  past  experience,  and  they  cannot  be  called 
into  existence  by  the  fancy.    Considered  in  the  light  of  results, 
pain  has  a  use  above  that  of  pleasure ;  for,  while  the  immod- 
erate pursuit  of  the  latter  leads  to  harm,  the  tendency  of  pain 
is  to  restrict  the  hurtful  courses  of  life,  and  in  this  manner  to 
protect  the  body. 

13.  The  relations  of  pain  to  pleasure  are  thus  described  by 
the  eminent  physiologist,  Magendie: — "By  these  sensations 
Nature  induces  us  to  concur  in  the  order  which  she  has  estab- 
lished among  organized  beings.     Though  it  may  appear  like 
sophistry  to  say  that  pain  is  the  shadow  of  pleasure,  yet  it  is 
certain  that  those  who  have  exhausted  the  ordinary  sources  of 
pleasure  have  recourse  to  the  causes  of  pain,  and  gratify  them- 
selves by  their  effects.     Do  we  not  see  in  all  large  cities,  that 
men  who  are  debauched  and  depraved  find  agreeable  sensations 
where  others  experience  only  intolerable  pain?"    (Head  Note  1.) 

1.  Pain  is  "Nature's  Harbinger  of  Mischief."  —  "It  must,  there- 
fore, be  evident  that  pain  is,  under  certain'circumstances,  really  beneficial. 
It  is  often  a  great  boon  to  have  a  sensitive  stomach  ;  for  those  who  suffer 
pain  after  food  are  less  apt  habitually  to  err  in  diet,  and  thus  to  become 
dyspeptic  or  gouty,  than  those  whose  organs  receive  everything  uncom- 
plainingly. Pain  in  the  stomach  is  frequently  due  (in  well-to-do  people) 
to  the  fact  that  they  won't  work  and  will  eat ;  not  that  the  stomach  itself 
is  weak  (as  they  think),  but  that  the  supply  of  food  being  greater  than 
the  demand,  the  system  becomes  overstocked.  In  dyspepsia  the  cause  is 
very  often  far  away,  and  the  stomach  is  no  more  the  cause  of  the  malady 


11.  The  case  of  the  traveler  ?    Grain  of  sand  ?    The  sun  and  child  ? 

12.  Mission  of  pain  ?    Painful  impressions  compared  with  those  of  pleasure? 
18.   What  does  Magendie  say  of  the  relation  of  pain  to  pleasure  ? 


THE  SPECIAL  SENSES  269 

14.  As  to  painful  sensation  among  the  inferior  animals,  the 
plan  of  Nature  seems  to  be,  that  the  higher  the  intelligence  of 
the  creature,  and  the  more  complete  its  power  of  defence,  the 
more  acute  is  its  sensibility.     We  infer,  therefore,  that  animals 
low  in  the  scale  of  existence,  and  helpless,  are  not  very  liable 
to  suffer  pain. 

15.  Special  Sensation.  —  The  sensations  of   simple  contact 
and  pain  are  felt  by  nearly  all  parts  of  the  system,  whether 
external  or  internal,  and  are  the  necessary  consequence  of  the 
general  sensibility ;  but,  so  far  as  the  objects  which  surround 
us  are  concerned,  these  impressions  are  vague  and  passive  in. 
character,  and  inform  the  mind  of  none  of  the  properties  or 
powers  of  these   objects.     Besides   these  feelings,  therefore, 
man  is  endowed  with  certain   special  sensations,  which  are 
positive  and  distinct  in  character,  and  which  he  can  call  into 
exercise  at  will,  and  employ  in  the  pursuit  of  knowledge.     For 
reasons  relating  to  the  original  constitution  of  the  body,  these 
sensations  are  to  be  regarded  as  modifications  of  the  general 
sensibility  already  alluded  to,  constructed  with  special  refer- 
ence to  the  different  forces  of  Nature  of  which  we  have  any 
knowledge,  such  as  heat,  motion,  gravity,  sunlight,  and  the 
like.     (Head  Note  2.) 

than  the  big  toe  is  of  the  gout ;  but  if  the  stomach  gave  no  signs  of  per- 
turbation, the  evil  would  be  allowed  longer  to  exist  unnoticed.  We  should 
always  give  early  attention  to  pain,  and  discover  its  causes  before  they 
become  too  complex  to  be  unraveled,  and  before  the  derangement  which 
its  presence  indicates  becomes  permanent.  The  following  incident  well 
illustrates  the  extent  to  which  pain  may  be  dependent  on  fancy:  'A 
butcher  was  brought  into  the  druggist's  from  the  market-place  opposite, 
laboring  under  a  terrible  accident.  The  man,  on  trying  to  hook  up  a 
heavy  piece  of  meat  above  his  head,  slipped,  and  the  sharp  hook  pene- 
trated his  arm  so  that  he  himself  was  suspended.  On  being  examined, 
he  was  pale,  almost  pulseless,  and  expressed  himself  as  suffering  acute 
agony.  The  arm  could  not  be  moved  without  causing  excessive  pain,  and 
in  cutting  off  the  sleeve  he  frequently  cried  out ;  yet,  when  the  arm  was 
exposed,  it  was  found  quite  uninjured,  the  hook  having  only  traversed 
the  sleeve  of  the  coat ! »  The  sensation  here  was  perfectly  real,  but 
originated  in  a  change  of  the  brain  and  nerves,  instead  of  in  the  external 
senses."  —  Notes  on  Pain. 

14.  The  lawT>f  Nature  as  regards  painful  sensations  among  animals  f 

15.  The  sensation  of  contact  and  pain  ?    Special  sensations  of  man  ?    How  regarded  f 


270  THE  SPECIAL  SENSES 

16.  These  distinct  and  active  faculties  are  termed  the 
special  senses,  and  are  five  in  number,  viz.,  Touch,  Taste, 
Smell,  Sight,  and  Hearing.  For  the  exercise  of  these  senses, 
special  organs  are  furnished,  such  as  the  hand,  the  tongue,  the 
nose,  the  eye,  and  the  ear.  The  manner  in  which  the  nerves 

2.  The  Mutual  Relations  of  the  Special  Senses.  —  "A  blind  man, 
attempting  to  express  his  notion  of  scarlet,  said  it  resembled  the  sound  of 
a  trumpet.  We  are  constantly  reminded  of  the  impressions  of  one  sense 
by  the  operations  of  another.  To  my  ear  the  bass  note  in  music  is  what 
a  dull  black  is  to  the  eye.  The  reverberations  of  deep  thunder  seem  like 
boulders  with  worn  angles  —  with  profiles  blunt  and  irregular,  as  if  drawn 
by  the  jerking  pencil  of  the  lightning ;  and  one  who  never  had  the  pleas- 
ure of  seeing  stars  from  a  blow  on  the  head  may  get  a  tolerably  correct 
idea  of  that  kind  of  galaxy  by  snuffing  at  a  bottle  of  volatile  salts. 

"  Language  is  full  of  effort  to  report  the  impressions  of  one  sense  by 
the  symbols  of  another.  We  say  that  an  apple  is  sweet,  that  a  rose  is 
sweet,  a  face  is  sweet,  a  strain  of  music  is  sweet,  and  love  is  sweet,  not 
to  mention  the  saccharine  reaction  of  the  '  uses  of  adversity. '  Here 
taste,  smell,  sight,  hearing,  and  a  social  sentiment  use  the  same  word  for 
that  pleasurable  sensation  experienced  by  the  mind  through  each  distinc- 
tive organ.  We  assist  the  organ  of  one  sense  by  that  of  another.  We 
open  the  lips  and  part  the  teeth  a  little  when  we  are  eager  to  hear  ;  we 
listen  and  turn  the  eyes'  attention  inward  when  we  would  detect  a  deli- 
cate taste,  or  remember  a  faded  impression. 

"  But  this  mutual  accommodation  of  the  senses  is  not  so  marvelous  as 
it  may  seem,  when  we  remember  that  the  whole  five,  six,  or  seven,  as  you 
please,  are  but  one  power  of  nervous  perception,  specialized  into  a  variety 
of  functions,  differentiated,  as  the  learned  say,  that  we  may  have  more 
perfect  work  by  a  division  of  labor.  The  same  necessity  which  developed 
nerve-contact  into  sight  on  the  one  hand  and  hearing  on  the  other  might 
also  express  through  one  of  these  the  sensations  proper  to  the  other,  when 
the  other  was  wanting.  Seal  up  the  eyes  of  a  bat,  say  the  naturalists, 
and  let  it  loose  in  a  room  crossed  with  wires  in  every  direction,  and  he 
will  fly  clear  of  them  all,  as  if  he  had  other  means  of  perception  as 
sensitive  as  the  optic  nerve. 

"Laura  Bridgman,  with  neither  sight,  hearing,  nor  smell,  could  detect 
the  presence  of  a  stranger  in  the  room,  without  contact.  Her  mind  then 
must  have  as  distinct  an  image  of  every  person  as  we  have,  yet  not  one 
of  what  we  call  our  senses  could  go  to  the  making  up  of  that  image.  It 
could  not  be  form  as  we  know  it,  nor  a  voice,  nor  an  odor,  but  it  was 
itself  other  than  all,  exciting  emotions  of  love,  or  hate,  gratitude  or 
repugnance,  and  the  thought  it  excited  must  have  had  shape,  though  it 
is  not  easy  to  imagine  how."  —  The  Schoolmaster. 


16.  What  are  the  special  senses  ?    Special  organs  for  them  ? 


THE  SPECIE     SENSES  271 

of  special  sense  terminate  varies1  n  the  case  of  each  organ,  so 
that  each  is  adapted  to  one  se~  of  sensations  alone,  and  is 
incapable  of  perceiving  any  othu-.  Thus  the  nerve  of  hearing 
is  excited  by  the  waves  of  sou^d,  and  not  by  those  of  light, 
while  the  reverse  is  true  of  the  nerve  of  sight ;  and  the  nerve 
of  smell  can  appreciate  neither  of  them,  being  capable  only 
of  taking  cognizance  of  the  odorous  properties  of  bodies. 
(Bead  Note  3.) 

17.  By  some  writers  six  senses  are  accorded  to  man,  the 
additional  one  being  either  the  sense  of  temperature  —  for,  as 
we  shall  presently  see,  this  is  not  the  same  as  touch  —  or, 
according   to   others,  the  muscular   sense   by  which   we   are 
enabled  to  estimate  the  weights  of  bodies.     The  latter  also 
differs  in  some  respects  from  the  sense  of  touch*. 

18.  Organs  of  Touch. — The  sense  of  touch  is  possessed  by 
nearly  all  portions  of  the  general  surface  of  the  body,  but  it 
finds  its  highest  development  in  the  hands.     The  human  hand 
is  properly  regarded  as  the  model  organ  of  touch.     The  minute 
structure  of  the  skin  fits  it  admirably  for  this  form  of  sensa- 
tion ;  the  cuticle,  or  scarf-skin,  is  fine  and  flexible,  while  the 
cutis,   or   true-skin,   contains    multitudes    of    nerve-filaments, 
arranged  in  rows  of  papillce  or  cone-like  projections,  about  one 
one-hundredth  of  an  inch  in  length.     It  is  estimated  that  there 
are  20,000  of  these  papillae  in  a  square-inch  of  the  palmar  sur- 
face of  the  hand.     Now,  although  the  nerves  of  the  cutis  are 
the  instruments  by  which  impressions  are  received  and  trans- 
mitted to  the  brain,  yet  the  cuticle  is  essential  to  the  sensation 
of  touch.     This  is  shown  by  the  fact  that  whenever  the  true- 
skin  is  laid  bare,  as  by  a  burn  or  blister,  the  only  feeling  that 
it  experiences  from  contact  is  one  of  pain,  not  that  of  touch. 

3.  Variation  in  Structure  in  the  Nerves  of  Special  Sense.  —  "  While 
in  the  more  intellectual  senses  —  Sight,  Hearing,  and  Touch  —  the  nerves 
have  their  protecting  and  isolating  sheaths  corresponding  with  the  dis- 
tinctness and  separateness  of  the  parts  of  the  impression,  in  Smell  the 
nerves  are  a  plexus  of  unsheathed  fibres,  corresponding  with  the  fusion  of 
the  odorous  impression  into  one  whole,  without  distinction  of  parts."  — 
Herbert  Spencer. 

17.  What  is  said  in  relation  to  one  more  than  the  five  senses  ? 

18.  The  sense  of  touch,  how  prevalent  ?    What  is  said  of  the  hand  ? 


272  THE  SPECIAL  SENSES 

19.  The  office  of  the  cuticle  is  thus  made  evident;  it  is  to 
shield  the  nerve-filaments  from  direct  contact  with  external  ob- 
jects.    At  the  tips  of  the  fingers,  where  touch  is  most  delicate, 
the  skin  rests  upon  a  cushion  of  elastic  material,  and  receives 
firmness  and  permanence  of  shape  by  means  of  the  nail  placed 
upon,  the  less  sensitive  side.     Besides  these  favorable  condi- 
tions, the  form  of  the  arm  is  such,  and  its  motions  are  so  easy 
and  varied,  that  we  are  able  to  apply  the  test  of  touch  in  a  great 
number  of  directions.     The  slender,  tapering  fingers,  with  their 
pliant  joints,  together  with  the  strong  opposing  thumb,  enable 
the  hand  to  grasp  a  great  variety  of  objects ;  so  that,  great  as 
are  the  delicacy  and  grace  of  the  hand,  it  is  not  wanting  in  the 
elements  of  power. 

20.  Its  beauty  and  adaptation  to  the  wants  of  man  have  made 
the  hand  an  attractive  theme  for  philosophers.     They  do  not, 
however,  always  agree  in  their  conclusions.     One  has  the  opin- 
ion that  man  has  acquired  his  intelligence  and  achieved  his 
place  as  "  lord  of  creation/'  because  he  has  this  organ.    Buffon, 
in  effect,  declares  that  with  fingers  twice  as  numerous,  and  twice 
as  long,  we  would  become  proportionally  wiser ;  but  Galen  long 
ago  took  a  more  reasonable  view,  when  he  taught  that  "  man 
is  the  wisest  of  animals,  not  because  he  possesses  the  hand,  but 
because  he  is  the  wisest,  and  understands  its  use ;  for  his  mind, 
not  his  hand,  has  taught  him  the  arts."     Another  has  well  said, 
that  "  no  one  can  study  carefully  the  human  hand  and  fail  to  be 
convinced  of  the  existence  of  the  Deity." 

21.  The  Sense  of  Touch.  — Touch  is  the  simplest  of  the  senses. 
It  is  that  which  the  child  first  calls  into  exercise  in  solving  the 
early  problems  of  existence,  and  it  is  that  which  is  in  the  most 
constant  use  throughout  life.     We  are  brought  by  the  touch 
into  the  most  intimate  relations  with  external  objects,  and  by 
it  we  learn  the  greater  number,  if  not  the  most  important,  of  the 
properties  of  these  objects,  such  as  size,  figure,  solidity,  motion, 
and  smoothness  or  roughness  of  surface. 


19.  Office  of  the  cuticle  ?    Tips  of  the  fingers  ?    The  fingers  with  thumb  ? 

20.  What  special  importance  is  attributed  to  the  hand  ? 

21.  The  simplicity  of  touch  ?    What  does  it  teach  us  ? 


THE  SPECIAL  SENSES  273 

22.  The  sense  of  touch  assists  the  other  senses,  especially 
that  of  sight,  giving  foundation  and  reality  to  their  perceptions. 
Without  it,  the  impressions  received  by  the  eye  would  be  as 
vague  and  unreal  as  the  figures  that  float  through  our  dreams. 
A  boy  who  had  been  blind  from  birth,  at  the  age  of  twelve 
years  received  sight  by  means  of  a  surgical  operation ;  at  first, 
he  was  unable  to  distinguish  between  a  globe  and  a  circular 
card  of  the  same  color  before  he  had  touched  them.     After 
that,  he  at  once  recognized  the  difference  in  their  form.     He 
knew  the  peculiarities  of  a  dog  and  a  cat  by  feeling,  but  not 
by  sight,  until  one  day,  happening  to  take  up  the  cat,  he  recog- 
nized the  connection  of  the  two  sorts  of  impressions --these  of 
touch  and  sight;  and  then,  putting  the  cat  down,  U3  sai^  : 
"  So,  Puss,  I  shall  know  you  next  time." 

23.  Of  all  the  senses,  touch  is  considered  the  least  liable  to 
error;  yet,  if  that  part  of  the  skin  by  which  the  sense  is 
exercised  is   removed   from  its   customary  position,   a  false 
impression  may  be  created  in  the  mind.     This  is  well  illus- 
trated by  an  experiment,  which  dates  from  the  time  of  Aris- 


Fio.  61 

totle.  If  we  cross  the  middle  finger  behind  the  forefinger, 
and  then  roll  a  marble  or  some  small  object  upon  the  tips  of 
the  fingers  (see  Fig.  61),  the  impression  will  be  that  two- mar- 
bles are  felt.  If  the  fingers,  thus  transposed,  be  applied  to 
the  end  of  the  tongue,  two  tongues  will  be  felt.  When  the 
nose  is  accidentally  destroyed,  the  surgeon  sometimes  performs 

22.  Importance  of  the  sense  of  touch  to  the  development  of  the  other  senses  ? 

23.  Liability  of  touch  to  err  ?    Describe  the  illustration. 


274  THE  SPECIAL  SENSES 

an  operation  for  the  purpose  of  forming  a  new  one,  by  trans- 
planting a  partially  removed  piece  of  the  skin  of  the  forehead 
upon  the  injured  part;  then,  if  the  new  nose  be  touched  or 
pinched,  the  feeling  is  referred  to  the  forehead.  This  fact 
illustrates  one  important  truth  —  that  the  nerves  will  re-unite 
after  they  have  been  cut  and  feeling  will  be  restored;  if  it 
were  otherwise,  a  succession  of  slight  cuts  upon  the  fingers 
would  seriously  impair  their  tactile  sensibility. 

24.  The   Delicacy   of   Touch. — Although   the  hand  is  the 
proper  organ  of  this  sense,  yet  it  is  exercised  by  various  parts 
of  the  body,  their  degree  of  sensibility  being  proportional  to 
the  number  of  papillae  they  contain.     The  varying  degrees  of 
tactile  delicacy  of  the  different  parts  of  the  surface  have  been 
measured  in  an  ingenious  manner,  by  means  of  a  pair  of  com- 
passes, tipped  with  small  pieces  of  cork.     The  two  points  of 
the  compasses  are  touched  at  the  same  moment  to  the  skin,  the 
eyes  being  closed,  and  it  is  found  that,  in  sensitive  parts,  the 
distance  between  the  points  may  be  quite  slight,  and  yet  each 
be  plainly  felt ;  while,  in  less  sensitive  parts,  the  points  of  the 
compasses  are  felt  as  a  single  point,  although  they  are  sepa- 
rated one  or  two  inches. 

25.  At  the  tips  of  the  fingers,  the   distance  between  the 
points  being  one-twentieth  of  an  inch,  a  double  impression  is 
felt.     The  distance  must  be  twice  as  great  for  the  palm,  four 
times  as  great  for  the  lips,  and,  on  the  forehead,  it  must  be 
twenty  times  greater.     At  the  middle  of  the  back,  where  the 
touch  is  least  acute,  the  points  must  be  separated  more  than 
two  inches  before  they  can  be  separately  felt.     Therefore,  the 
sense  of  touch  in  the  fingers  is  said  to  be  fifty  times  more 
delicate  than  upon  the  posterior  surface  of  the  body. 

26.  Exquisite   delicacy   of  touch  is   attained   by  practice. 
This   is   shown   in  many  of  the   lighter   and  more  graceful 
employments   of    daily   life.      Without   it,   the   skill    of    the 
painter,  sculptor,  and  musician  would  be  rude  indeed.     By 

24.  The  delicacy  of  touch  ?    Experiments  with  a  pair  of  compasses  ? 

25.  Further  experiments  and  results  ? 

26.  Exquisite  delicacy  of  touch  ?    The  same  among  the  blind  f 


THE  SPECIAL  SENSES  275 

training,  also,  the  physician  acquires  the  tactus  eruditus,  or 
discriminating  touch ;  but  among  the  blind,  delicacy  of  touch 
is  most  remarkable,  and  it  there  finds  its  highest  value ;  for 
its  possession,  in  a  measure,  compensates  for  the  loss  of  sight 
by  enabling  them  to  read,  by  means  of  raised  letters,  to  work 
with  certain  tools,  and  even  to  play  upon  musical  instruments. 
A  person  born  without  sight,  and  without  hearing  or  voice, 
may,  by  the  education  of  the  touch,  be  rescued  from  apparent 
imbecility,  and  be  taught  not  only  to  read  and  write,  but  even 
to  perform  household  and  other  useful  labors. 

27.  Sensations  of  Temperature  and  Weight.  —  Each  of  these 
sensations  has  been  described  by  the  physiologists  as  a  special 
sense,  and  they  are  rival  candidates,  so  to  speak,  for  the  posi- 
tion and  title  of  the  sixth  sense.  In  the  sensation  of  temper- 
ature, or  the  thermal  sense,  touch  bears  a  part,  but  the  two 
feelings  appear  to  be  distinct.  In  proof  of  this,  we  observe, 
firstly,  that  they  are  not  alike  intense  in  the  same  situations ; 
as,  for  example,  the  skin  of  the  face  and  elbow,  where  the 
sense  of  touch  is  feeble,  is  very  sensitive  to  impressions  of 
heat  and  cold.  Secondly,  the  ability  to  recognize  temperature 
may  be  lost  by  paralysis,  while  the  sensibility  of  touch  remains 
unaffected.  When  the  skin  comes  in  contact  with  a  very  hot 
substance,  the  sensation  felt  is  that  of  pain  —  not  of  touch. 
In  like  manner,  a  very  cold  substance  causes  pain,  not  the 
feeling  of  cold.  So  that  a  red-hot  iron,  and  solid  carbonic  acid 
(the  temperature  of  which  is  108°  below  zero),  feel  alike ;  and 
each,  if  pressed  slightly,  will  produce  a  blister.  {Read  Note  4.) 

4.  Qualities  Determined  by  the  Sense  of  Touch.  —  "The  eye,  by 
the  aid  of  certain  signs,  is  often  able  to  tell  whether  a  body  is  hot  — 
when,  for  instance,  it  is  glowing  or  steaming  —  but  a  perception  of 
warmth  is  not  possessed  by  the  eye.  This  is  had  by  the  skin  alone, 
and  it  is  of  great  importance  to  our  preservation  that  this  property  is 
spread  over  the  entire  surface ;  for  it  surrounds  the  body  like  a  pro- 
tecting wall  against  its  worst  enemy  —  cold  —  which,  if  not  thus  guarded 
against  at  all  points,  would  speedily  destroy  life.  We  are  warned,  how- 
ever, of  the  approach  of  the  enemy  by  a  common  sensation  of  the 
skin,  and  an  inward  chill,  which  is  only  caused  by  a  coolness  of  the 


27.  Rival  candidates  for  the  sixth  sense  ?    Give  the  two  reasons  on  the  subject. 


276  THE  SPECIAL  SENSES 

28.  The  muscular  sense,  by  some  considered  distinct  from 
touch,  gives  rise  to  the  sensations  of  weight,  and  other  forms 
of  external  resistance.     That  this  feeling  exists,  is  shown  by 
the  following  simple  experiment :  if  the  hand  be  placed  flat 
upon  a  table,  and  a  somewhat  heavy  weight  be  put  into  it, 
touch  alone  is  exercised,  and  a  feeling  of  pressure  results ;  but 
if  the  hand  be  raised,  a  certain  amount  of  muscular  effort  must 
be  put  forth,  and  thus  the  sensation  of  wreight  is  recognized. 
Through  the  muscular  sense,  precision  of  effort  is  rendered  pos- 
sible ;  for  by  it  we  learn  to  adjust  the  force  exerted  to  the 
weight  of  the  object  to  be  lifted,  moved,  or  carried.     Without 
it  all  our  movements  would  necessarily  become  ill-regulated 
and  spasmodic.     In  cases  of  disease,  where  the  sensibility  of 
the  lower  limbs  is  lost  while  power  of  motion  remains,  the 
patient  is  able  to  stand  erect  so  long  as  he  can  see  his  limbs ; 
but  just  as  soon  as  his  eyes  are  closed,  he  begins  to  waver,  and 
will  fall  unless  supported. 

29.  The  Organ  of  Taste.  —  The  tongue  is  the  special  organ 
of  the  sense  of  taste ;  but  the  back  part  of  the  mouth  always 
possesses  this  faculty.     The  tongue  is  a  muscular  organ,  the 

skin.  The  skin,  in  like  manner,  protects  the  body  against  the  approach 
of  a  hurtful  degree  of  heat.  Thus,  you  see,  the  skin  has  certain  quali- 
ties of  sensation.  Just  as  the  eye,  in  looking  at  a  wafer,  perceives 
that  it  is  both  red  and  circular,  distinguishing  both  the  color  and  form 
of  bodies,  so  the  sensitive  skin  by  contact  with  an  object  distinguishes 
the  qualities  of  form,  firmness,  hardness,  liquidity,  pressure,  and  tempera- 
ture. *  *  *  Weber  has  discovered  the  interesting  fact  that  warm 
bodies  feel  lighter  than  cold  ones  :  if  a  cold  coin  be  placed  upon  the 
forehead  of  some  person,  whose  eyes  are  shut,  and  then  upon  the  same 
spot  two  warm  coins,  the  weight  would  seem  to  him  the  same,  whilst 
he  could  distinguish  correctly  in  the  case  of  cold  weights.  *  *  *  If 
we  place  the  elbow  in  hot  water,  we  experience  heat  only  in  the  part 
immersed,  not  in  the  whole  arm,  although  the  nerve  just  under  the  skin 
runs  throughout  the  arm  and  hand.  What  we  feel  is  a  dull  sense  of 
pain  in  the  whole  arm  if  the  water  is  too  hot.  So,  too,  if  the  elbow 
is  placed  in  ice- water  the  pain  is  just  the  same  in  the  arm  ;  proving 
that  the  nerve  trunk  can  feel  neither  warmth  nor  cold."  —  Bernstein1  s 
Five  Senses  of  Man. 

28.  The  muscular  sense?    State  what  is  said  to  illustrate  the  subject, 

29.  The  organ  of  taste  ?    The  tongue  ?    Its  powers  of  motion  ? 


THE  SPECIAL  SENSES  277 

muscles  composing  it  being  so  numerous  and  interwoven  as  to 
give  it  the  freedom  and  variety  of  motion  which  it  possesses. 
It  can  curve  itself  upward  or  downward ;  it  can  extend  or  con- 
tract itself;  and,  with  its  point,  can  sweep  the  cavity  of  the 
mouth,  in  all  directions,  in  the  search  for  scattered  particles  of 
food. 

30.  The  upper  surface  of   the   tongue   is   peculiar,   being 
marked  by  the  presence  of  innumerable  papillae,  some  of  which 
are  of  microscopic  size,  resembling  those  that  abound  in  the 
lingers,  and  in  other  parts  of  the  body  that  have  the  sense  of 
touch.     Others  are  much  larger,  and  give  to  the  tongue  its 
roughness  of  feeling  and  appearance.     Through  the  medium 
of  these  papillae,  the  tongue  receives  impressions  of  touch  and 
temperature,  as  well  as  taste :  indeed,  its  extremity  is  fully  as 
delicate,  in  respect  to  tactile  sensations,  as  the  tips  of  the  fin- 
gers themselves.     It  can  recognize  the  two  points  of  the  com- 
passes when  separated  not  more  than  one  twenty-fourth  of  an 
inch ;  the  back  of  it  is  much  less  sensitive  to  touch,  while  at 
the  same  time  it  is  more  highly  sensitive  to  impression  of 
taste.  . 

31.  Each  lateral  half  of  the  tongue  resembles  the  other  in 
structure,  and  each  receives-  the  same  number  of  nerves  — 
three.    One  of  these  regulates  motion,  the  other  two  are  nerves 
of  special  sense.      One  of  the  latter  supplies  the  front  half 
of  the  tongue,  and  is  called  the  gustatory  nerve.     This  is  a 
branch  of  the  great  cranial  nerve,  called  the  "  fifth  pair,"  which 
ramifies  in  all  parts  of  the  face.     The  back  of  the  tongue  is 
endowed  with  the  power  of  taste, -through  a  nerve  known  as 
the  glosso-pharyngeal,   because   it   is   distributed  both  to  the 
tongue  and  throat.     This  difference  in  the  nervous  supply  of 
the  tongue  becomes  significant,  when  we  learn,  as  we  shall 
presently,  that  each  part  of  it  perceives  a  different  class  of 
flavors. 

32.  The  Sense  of  Taste.  — Taste  is  the  special  sense  by  means 

30.  Peculiarities  of  the  tongue  ?     Uses  of  the  papillae  ? 

31.  Resemblance  in  the  parts  of  the  tongue  ?    Powers  and  functions  of  the  parts  ? 

32.  Taste?    What  are  the  requisites  to  taste  ? 


278  THE  SPECIAL  SENSES 

%f  which  we  discover  the  savors,  or  flavoring  properties  of  the 
substances  which  come  in  contact  with  the  tongue.  Mere  con- 
tact with  the  surface  of  the  tongue,  however,  is  not  sufficient, 
but  contact  with  the  extremities  of  the  nerves  of  taste  within 
the  papillae  is  required.  In  order  that  the  substance  to  be 
tasted  may  penetrate  the  cells  covering  the  nerves,  it  must 
either  be  liquid  in  form,  or  readily  soluble  in  the  watery  secre- 
tion of  the  mouth  —  the  saliva.  The  tongue  must  be  moist 
also.  If  the  substance  be  insoluble  —  as  glass  or  sand  —  or 
the  tongue  dry,  the  sense  of  taste  is  not  awakened.  In  sick- 
ness, when  the  tongue  is  heavily  coated,  the  taste  is  very  defec- 
tive, or,  as  is  frequently  said,  "  nothing  tastes  aright.'7 

33.  All  portions  of  the  tongue  are  not  alike  endowed  with 
the  sense  of  taste,  that  function  being  limited  to  the  posterior 
third,  and  to  the  margin  and  tip  of  this  organ.  The  soft  pal- 
ate, also,  possesses  the  sense  of  taste;  hence,  an  article  that 
has  an  agreeable  flavor  may  very  properly  be  spoken  of  as  pal- 
atable, as  is  often  done.  All  parts  of  the  tongue  do  not  per- 
ceive equally  well  the  same  flavors.  Thus,  the  front  extremity 
and  margin,  which  is  the  portion  supplied  by  the  "  fifth  pair  " 
of  nerves,  perceives  more  acutely  sweet  and  sour  tastes ;  but 
the  base  of  the  tongue,  supplied  by  the  glosso-pharyngeal  nerve, 
is  especially  sensitive  to  salt  and  bitter  substances.  The  nerve 
of  the  front  part  of  the  tongue,  as  before  stated,  is  in  active 
sympathy  with  those  of  the  face,  while  the  relations  of  the 
other  nerve  are  chiefly  with  the  throat  and  stomach ;  so  that 
when  an  intensely  sour  taste  is  perceived,  the  countenance  is 
involuntarily  distorted,  and  is  said  to  wear  an  acid  expression. 
On  the  other  hand,  a  very  bitter  taste  affects  certain  internal 
organs,  and  occasions  a  sensation  of  nausea,  or  sickness  of  the 
stomach.  (Head  Note  5.) 

5.  Flavors  and  Sense  of  Taste.  —  "The  cause  and  intimate  nature 
of  tastes  are  no  better  understood  than  those  of  odors.  Flavors  elude 
analysis  and  defy  classification,  even  that  which  divides  them  into  agree- 
able and  disagreeable,  for  the  taste  of  individuals  and  of  nations  singu- 
larly differs  in  this  respect.  The  Laplander  and  the  Esquimau  drink 


33.   Portions  of  the  tongue  endpwed  with  taste  ?     Where  else  does  the  sense  lodge  ? 
What  is  stated  in  respect  to  sweet  and  bitter  flavors  ?    Reflex  effects  mentioned  ? 


THE  SPECIAL  SENSES  279 


34.  Relations  of  Taste  with  other  Senses. — Taste  is  not  a 
simple  sense.    Certain  other  sensations,  as  those  of  touch,  tem- 
perature, smell,  and  pain,  are  blended  and  confused  with  it; 
and  certain  so-called  tastes  are  really  sensations  of  another 
kind.     Thus  an  astringent  taste,  like  that  of  alum,  is  more 
properly  an  astringent  feeling,  and  results  from  an  impression 
made  upon  the  nerves  of  touch  that  ramify  in  the  tongue.     In 
like  manner,  the  qualities  known  as  smooth,  oily,  watery,  and 
mealy  tastes,  are  dependent  upon  these  same  nerves  of  touch. 
A  burning  or  pungent  taste  is  a  sensation  of  pain,  having  its 
seat  in  the  tongue  and  throat.     A  cooling  taste,  like  that  of 
mint,  pertains  to  that  modification  of  touch  called  the  sense  of 
temperature. 

35.  Taste  is  largely  dependent  upon  the  sense  of  smell.     A 
considerable  number  of  substances,  like  vanilla,  coffee,  and  gar- 
lic, which  appear  to  possess  a  strong  and  distinct  flavor,  have 
in  reality  a  powerful  odor,  but  only  a  feeble  taste.     When  the 
sense  of  smell  is  interfered  with  by  holding  the  nose",  it  becomes 
difficult  to  distinguish  between  substances  of  this  class.     The 


great  quantities  of  train-oil,  which  for  them  is  a  greatly-esteemed 
article  of  food,  and  is  most  admirably  adapted  to  the  exigencies  of  a 
Polar  climate ;  the  Abyssinians  eat  raw  flesh,  and  find  its  flavor 
excellent,  while  the  inhabitant  of  the  West  partakes  of  it  with  the 
greatest  repugnance  and  only  as  a  medicine.  Oysters,  which  are  so 
generally  esteemed  in  our  country,  are  to  some  persons  disagreeable 
and  nauseous;  and  truffles,  the  delight  of  the  gourmand,  are  rejected 
by  the  uninitiated  on  account  of  their  flavor  and  their  perfume.  It  is 
the  same  with  almost  all  alimentary  substances ;  they  are  eagerly 
sought  after  by  some,  and  despised  or  abhorred  by  others.  Let  us 
remember  the  proverb  '  de  gustibus  non  disputandumS  and  not  dispute 
in  regard  to  tastes  ;  each  is  suited  to  its  own  country,  and  goodly 
numbers  acclimatize  themselves,  to  the  great  advantage  of  peoples 
among  whom  at  first  they  seem  exceedingly  strange.  Man  should 
control  his  taste,  and  habituate  it  to  all  wholesome  aliment ;  this 
neither  excludes  choice,  nor  blunts  the  delicacy  of  the  sense  ;  and 
while  we  resist  its  seductions,  we  should  give  timely  heed  to  its 
instincts  and  its  counsels,  for  they  are  often  invaluable." — The  Won- 
ders of  the  Human  Body. 


34.  What  is  stated  of  the  relations  of  taste  to  the  other  senses  ? 
85.   Its  dependence  on  smell  ?  on  sight  ? 


280  THE  SPECIAL  SENSES 

same  effect  is  frequently  observed  when  smell  is  blunted  during 
an  ordinary  cold  in  the  head.  Sight  also  contributes  to  taste. 
With  the  eyes  closed,  food  appears  comparatively  insipid ;  and 
a  person  smoking  tobacco  in  the  dark  is  unable  to  determine  by 
the  taste  whether  his  cigar  is  lighted  or  not.  Accordingly,  it 
is  not  a  bad  plan  to  close  the  nose  and  shut  the  eyes  when 
about  to  swallow  some  disagreeable  medicine. 

36.  Influence  of  Education  on  the  Taste.  —  The  chief  use  of 
the   sense   of  taste   appears   to  be  to  act  as  a  guide  in  the 
selection  of  proper  food.     Hence  its  organs  are  properly  placed 
at  the   entrance   of  the  digestive  canal.     As   a  general  rule, 
those  articles  which  gratify  the  taste  are  wholesome  5  while  the 
opposite  is  true  of  those  which  impress  it  disagreeably.     This 
statement  is  more  exact  in  reference  to  the  early  than  to  the 
later  years  of  life,  when,  by  reason  of  improper  indulgence,  the 
sense  of  taste  has  become  dulled  or  perverted.     The  desires  of 
a  child  are  simple ;  he  is  fully  satisfied  with  plain  and  whole- 
some articles  of  diet,  and  must  usually  "learn  to  like"  those 
which  have  a  strongly  marked  flavor.     Accordingly,  it  is  far 
easier  at  this  age  to  encourage  the  preference  for  plain  food, 
and  thus  establish  healthful  habits,  than  later  in  life  to  uproot 
habits  of  indulgence  in  stimulating  substances,  after  their  ill 
effects  begin  to  manifest  themselves. 

37.  The  tastes  of  men  present  the  most  singular  diversities, 
partly  the  result  of  necessity  and  partly  of  habit  or  education. 
The  Esquimaux  like  the  rank  smell  of  whale-oil,  which  is  a 
kind  of  food  admirably  suited  to  the  requirements  of  their  icy 
climate ;  and  travelers  who  go  from  our  climate  to  theirs  are 
not  slow  to  develop  a  liking  for  the  same   articles   that  the 
natives  themselves  enjoy.     The  sense  of  taste  is  rendered  very 
acute  by  education,  as  is  shown  in  an  especial  manner  by  those 
who  become  professional  "tasters  "  of  tea  and  wine. 

38.  The  Sense  of  Smell  —  the  Nasal  Cavities. — The  sense  of 
smell  is  located  in  the  delicate  mucous  membrane  which  lines 

86.  The  chief  use  of  the  sense  ui'  taste  ?     The  position  of  the  organs  ?     The  rule  as 
regards  wholesome  and  unwholesome  food  ?    Kemarks  respecting  the  rule  ? 

37.  Diversity  in  tastes  of  men  ?    How  shown  ?    The  education  of  the  sense  of  taste  ? 

38.  Location  of  the  sense  of  smell  ?    The  nose  ?    "  Koof  of  the  mouth  ?  " 


THE  SPECIAL  SENSES  281 

the  interior  of  the  nose.  That  prominent  feature  of  the  face, 
the  nose,  which  is  merely  the  front  boundary  of  the  true  nasal 
« uLruii,  is  composed  partly  of  bone  and  partly  of  cartilage.  The 
upper  part  of  it  is  united  with  the  skull  by  means  of  a  few 
small  bones,  to  which  circumstance  is  due  its  permanence  of 
shape.  The  lower  portion,  or  tip  of  the  nose,  contains  several 
thin  pieces  of  cartilage,  which  render  it  flexible  and  better  able 
to  resist  the  effects  of  blows  and  pressure.  Behind  the  nose  we 
find  quite  a  spacious  chamber,  separated  from  the  mouth  by 
the  hard  palate,  forming  the  "  roof  of  the  mouth,"  and  also  by 
the  soft  palate  (see  Fig.  62) ;  and  divided  into  two  cavities  by  a 
central  partition  running  from  before  backward. 

39.  These  nasal  cavities,  constituting  the  true  beginning  of 
the  air-passages,  extend  from  the  nose  backward  to  the  upper 
opening  of  the  throat,  and  rise  as  high  as  the  junction  of  the 
nose  with  the  forehead.     The  inner  wall  of  each  cavity  is 
straight  and  smooth ;  but  from  the  outer  wall  there  jut  into 
each  cavity  three  small  scroll-like  bones.     The  structure  of 
these  bones  is  very  light,  and  hence  they  have  been  called  the 
"  spongy  "  bones  of  the  nose.     In  this  manner,  while  the  extent 
of  surface  is  greatly  increased  by  the  formation  of  these  wind- 
ing passages,  the  cavities  are  rendered  extremely  narrow;  so 
much  so,  in  fact,  that  a  moderate  swelling  of  the  mucous  mem- 
brane which  lines  them,  as  from  a  cold,  is  sufficient  to  obstruct 
the  passage  of  air  through  them. 

40.  The  Nerve  of  Smell.  —  The  internal  surface  of  the  nasal 
passages  is  covered  by  a  delicate  and  sensitive  mucous  mem- 
brane.    Its  surface  is  quite  extensive,  following  as  it  does  all 
the  inequalities  produced  by  the  curved  spongy  bones  of  the 
nose.     Only  the  upper  portion  of  it  is  the  seat  of  smell,  since 
that  part  alone  receives  branches  from  the  "first  pair"  of 
cranial  nerves,  or  the  olfactory  nerve,  which  is  the  special 
nerve  of  smell  (see  Fig.  62).     In  Fig.  62  is  shown  the  distribu- 
tion of  this  nerve,  in  the  form  of  an  intricate  network  upon  the 
two  upper  spongy  bones.     The  nerve  itself  (1)  does  not  issue 

89.   Cavities  of  the  nose  ?    Obstruction  of  the  passage  of  air  through  them  ? 
40.  The  special  nerve  of  smell  ?    Its  location  ? 


282 


THE  SPECIAL  SENSES 


from  the  skull,  but  rests  upon  a  thin  bone  which  separates 
it  from  the  cavity  of  the  nose ,  and  the  branches  which'  proceed 
from  it  pass  through  this  bone  by  means  of  numerous  small 
openings.  The  engraving  represents  the  outer  surface  of  the 
right  nasal  cavity;  the  three  wave-like  inequalities,  upon  '.which 
the  nervous  network  is  spread  out,  are  due  to  the  spongy  frones. 
The  left  cavity  is  supplied  in  the  same  manner. 

41.  The  nerves  which  ramify  over,  the  lower   part  of  the 
membrane,  and  which  endow  it  with  sensibility  to  toucfy  and 
pain,  are  branches  of  the 

"  fifth  pair "  of  nerves. 
An  irritation  applied  to 
the  parts  where  this  nerve 
is  distributed  occasions 
sneezing — that  is,  a  spas- 
modic contraction  of  the 
diaphragm,  the  object  of 
which  is  the  expulsion  of 
the  irritating  cause.  The 
manner  in  which  the  ol- 
factory nerve-fibres  termi-  •  Fio-  62,- SECTION  or  THK  EIGHT  NASAL  CAVITY 

nate  is  peculiar.  Unlike  the  extremities  of  other  nervesr^rjiich 
are  enclosed  by  a  greater  or  less- thickness  of  tissue,  these  come 
directly  to  the  surface  of  the  mucous  membrane,  and  thus  are 
in  very  close  contact  with  the.  odorous  particles  that  are  carried 
along  by  the  respired  air.  The  surface  is  at  all  times  kept  in 
a  moist  condition  by  an  abundant  flow  of  nasal  mucus;  other- 
wise it  would  become  dry,  hard,  and  insensitive  from  the  con- 
tinual passage  of  air  to  and  fro  in  breathing.  Birds,  which 
respire  more  actively  than  men,  have  a  special  gland  for  secret- 
ing a  lubricating  fluid,  located  in  the  air-passages  of  the  Jiead. 

42.  The  Uses  of  the  Sense  of  Smell.  —  Smell  is  the  special 
sense  which  enables  us  to  appreciate  odors.     Touch,  as  we  have 
seen,  is  largely  concerned  with  solid  bodies,  and  taste   with 


4U  Branches  of  the  "  fifth  pair"  of  nerves  ?    Nasal  mucus  ?     Birds? 
42.   Smell  ?    Touch  ?    Taste  ?    Design  of  smell  ?    Invisible  and  gaseous  particles  ?    The 
extreme  fineness  of  the  particles  ?    Musk  ?    In  other  cases  ? 


THE  SPECIAL  SENSES  283 

fluids,  or  with  solids  in  solution.  Smell,  on  the  other  hand,  is 
designed  to  afford  us  information  in  reference  to  substances 
in  a  volatile  or  gaseous  form.  Invisible  particles  issue  from 
odorous  bodies  and  are  brought  by  the  respired  air  in  contact 
with  the  terminal  filaments  of  the  olfactory  nerve,  upon  which 
an  agreeable  or  disagreeable  impression  is  produced.  The  fine- 
ness of  the  particles  that  constitute  odors  is  often  so  extreme 
that  they  elude  all  attempts  to  measure  or  weigh  them.  A 
piece  of  musk,  for  instance,  may  be  kept  for  several  years, 
constantly  emitting  perfume  without  any  appreciable  loss  o4? 
weight.  In  other  cases,  a  loss  of  substance  is  perceptible,  as 
in  the  essential  oils,  which  enter  into  the  composition  of  the 
ordinary  perfumes. 

43.  Smell,  like  taste,  aids  us  in  the  choice  of  proper  food, 
leading  us  to  reject  such  articles  as  have  a  rank  or  putrid  odor, 
and  which  are,  as  a  rule,  unfit  to  be  eaten.  The  highest  use- 
fulness of  this  sense,  however,  consists  in  the  protection  it 
affords  to  the  organs  of  respiration.  Stationed  at  the  gateways 
of  the  air-passages,  it  examines  the  current  of  air  as  it  enters, 
and  warns  us  of.  the  presence  of  noxious  gases,  and  of  other  and 
generally  invisible  enemies  to  health.  Not  all  dangerous  vapors 
are  offensive,  but  almost  all  offensive  vapors  are  unfit  to  be 
breathed.  A  number  of  small  stiff  hairs  grow  from  the  margin 
of  the  nostrils  to  prevent  the  entrance  of  dust  and  other  atmos- 
pheric impurities,  which  would  be  alike  injurious  to. the  olfac- 
•tory  mucous  membrane  and  to  the  lungs.  The  benevolent 
design  of  the  Maker  of  our  bodies  may  be  observed  in  all  parts 
of  their  mechanism;  but,  probably,  in  none  is  it  more  clearly 
displayed  than  in  connection  with  the  sense  of  smell.  (Bead 
Note  6.) 

6.  The  Protective  Function  of  the  Sense  t)f  Smell.  —  "  Smell  seems 
to  be  regarded  as  an  endowment  bestowed  simply  for  pleasure,  serving  to 
promote  no  important  or  vital  end.  That  its  main  use  is  to  signal  danger 
to  internal  parts  is  not  duly  appreciated.  The  detection  of  an  offensive 
odor  is  thought  to  be  the  only  bad  thing  about  it,  and  which,  to  those 
habituated  to  it,  is  of  no  subsequent  importance.  Men  even  pride  them- 
selves on  becoming  accustomed  to  offensive  odors,  and  quite  enjoy  the 


43.  Aid  given  by  smell  ?    The  highest  use  of  the  sense  ?    Explain  the  mainer 


284  THE  SPECIAL  SENSES 

44.  The  sense  of  smell  is  developed  in  a  remarkable  degree 
in  certain  of  the  inferior  animals,  and  is  especially  acute  in 
reference  to  the  peculiar  odors  that  characterize  the  different 
animals.  The  lion  and  other  carnivorous  beasts  scent  their 
prey  from  a  great  distance ;  and  the  fox-hound  is  able  to  track 
the  fox  through  thickets  and  over  open  country  for  many  miles ; 
while  the  timid,  helpless  herbivora,  such  as  the  deer  and  sheep, 
find  in  the  sense  of  smell  a  means  of  protection  against  their 
natural  enemies,  of  whose  approach  they  are  in  this  manner 
warned.  By  training  this  sense  in  the  dog,  and  making  it  sub- 
servient to  his  use,  man  is  able  to  hunt  with  success  certain  shy 
and  very  fleet  animals,  which  otherwise  he  could  but  seldom 
approach.  Among  men,  individuals  differ  greatly  in  respect  to 
the  development  of  this  sense ;  and  especially  in  certain  savage 
tribes  it  is  found  to  be  extremely  delicate.  Humboldt  states 
that  the  natives  of  Peru  can  by  it  distinguish  in  the  dark 
between  persons  of  different  races.  (Mead  Note  7.) 

sight  of  one  whose  nerve  of  smell  is  not  benumbed  like  their  own.  In- 
stead of  seeking  to  blunt  the  sensibilities  of  this  nerve,  it  should  be  a 
study  to  improve  it,  as  the  most  delicate  and  available  test  of  air  im- 
purity—  far  superior,  under  ordinary  circumstances,  to  the  tests  of 
science.  In  this  way  all  ordinary  atmospheric  impurities  may  be  quickly 
detected  ;  and  it  is  truly  remarkable  how,  by  a  little  attention,  this  sense 
can  be  so  improved  as  to  detect  instantly  even  slight  impurities  to 
which  it  had  before  been  insensible.  In  many  houses,  by  the  total 
neglect  of  this  sense,  there  is  an  ever-present  family  odor,  produced  by 
some  special  kind  of  household  impurity,  and  of  which  the  inmates  do- 
not  seem  to  be  aware.  To  thpse  accustomed  to  pure  air,  house  odors  are 
always  perceptible  and  disagreeable.  This  ought  to  be  accepted  as  suffi- 
cient evidence  of  their  unhealthful  tendencies  ;  not  perhaps  of  an  instant 
or  violent  sort,  yet  enough  so  to  give  rise  to  many  sensations  of  slight  dis- 
comfort, and  producing,  when  long  continued,  a  state  of  the  body  very 
favorable  to  the  beginning  and  growth  of  virulent  diseases." — Blacks 
Ten  Laws  of  Health. 

7.  The  Effects  of  Certain  Odors.  —  "I  have  not  seen  it  anywhere  laid 
down  as  a  general  rule,  but  I  believe  it  might  be  affirmed,  that  we  are 
intended  to  be  impressed  only  sparingly  and  transiently  by  odor.  There 
is  a  provision  for  this  in  the  fact  that  all  odors  are  vapors  or  gases,  or 
otherwise  volatile  substances ;  so  that  they  touch  but  the  inside  of  the 
nostril,  and  then  pass  away. 


44.  Sense  of  smell  in  inferior  animals  ?    How,  and  in  what  cases  illustrated  ? 


THE  SPECIAL  SENSES  285 

45.  The  Sense  of  Sight.  —  Sight,  or  vision,  is  the  special 
sense  by  means  of  which  we  appreciate  the  color,  form,  size, 
distance,  and  other  physical  properties  of  the  objects  of  exter- 
nal nature.     Primarily,  this  sense  furnishes  us  with  informa- 
tion concerning  the  different  shades  of  color  and  the  different 
degrees  of  brightness  :  these  are  the  simple  sensations  of  sight, 
such  as  the  yellowness  and  glitter  of  a  gold  coin.     In  addition 
to  these,  there  are  composite  visual  sensations,  produced  by  the 
joint  action  of  the  other  senses  and  by  the  use  of  the  memory 
and  judgment ;  such  as,  in  the  case  of  the  coin,  its  roundness, 
solidity,  size,  its  distance  and  direction  from  us.    So  that  many 
of  our  sensations,  commonly  considered  as  due  to  sight,  are  in 
reality  the  results  of  intellectual  processes  which  take  place 
instantaneously  and  unconsciously. 

46.  This  faculty  not  only  is  valuable  in  the  practical  every- 
day affairs  of  life,  but  it  contributes  so  largely  to  the  culture 
of  the  intellect  and  to  our  higher  forms  of  pleasure,  that  some 
writers  are  disposed  to  rate  it  as  the  first  and  most  valuable  of 
the  senses.     Others,  however,  maintain  that  the  sense  of  hear- 
ing does  not  yield  in  importance  to  that  of  sight ;  and  they  cite 

"In  conformity  with  this  fleeting  character  of  odorous  bodies,  it  is  a 
law  in  reference  to  ourselves,  to  which,  as  far  as  I  know,  there  is  no 
exception,  that  there  is  not  any  substance  having  a  powerful  smell  of 
which  it  is  safe  to  take  much  internally.  The  most  familiar  poisonous 
vegetables,  such  as  the  poppy,  hemlock,  henbane,  monk's-hood,  and  the 
plants  containing  prussic  acid,  have  all  a  strong  and  peculiar  smell. 
Nitric,  muriatic,  acetic,  and  other  corrosive  acids,  have  characteristic 
potent  odors,  and  all  are  poisons.  Even  bodies  with  agreeable  odors, 
like  oil  of  roses,  or  cinnamon,  or  lavender,  are  wholesome  only  in  very 
small  quantities,  and,  when  the  odor  is  repulsive,  only  ic  the  smallest 
quantities.  So  far  as  health  is  concerned,  the  nostril  iaould  be  but 
sparingly  gratified  with  pleasing  odors  or  distressed  by  ungrateful  ones. 
No  greater  mistake  can  be  made  in  sick-rooms  than  dealing  largely  in 
aromatic  vinegar,  eau  de  cologne,  lavender  water,  and  other  perfumes. 
This  hiding  of  one  odor  by  another  is  like  trying  to  put  away  the  taste  of 
bitter  aloes  by  that  of  Epsom  salts.  Physical  comfort  is  best  secured  by 
rarely  permitting  an  infraction  of  the  rule  that  the  condition  of  health  is 
no  odor  at  all." —  Wilson  on  the  Five  Gateways  of  Knowledge. 


45.  What  is  sight?    What  information  does  it  furnish  ?    Composite  visual  sensation*  I 
4&  Comparison  between  sight  and  hearing  ?    Relative  capacity  of  deaf  and  blind  ? 


THE  SPECIAL  SENSES 

in  support  of  their  position  the  fact  that  the  blind  are  com- 
monly cheerful  and  gay,  while  the  deaf  are  inclined  to  be 
morose  and  melancholy.  In  respect  to  the  .relative  capacity 
for  receiving  education  in  the  deaf  and  blind,  it  is  found  that 
the  former  learn  more  quickly,  but  their  attainments  are  not 
profound ;  while  the  blind  acquire  more  slowly,  but  are  able 
to  study  more  thoroughly. 

47.  Light — The  Optic  Nerve.  —  Unlike  the  senses  previously 
considered  —  touch,  taste,  and  smell  —  sight  does  not  bring  us 
Into  immediate  contact  with  the  bodies  that  are  examined ;  but, 
by  it,  we  perceive  the  existence  and  qualities  of  objects  that  are 
at  a  greater  or  less  distance  from  us.     In  the  case  of  the  stars, 
the  distance  is  incalculable,  while  the  book  we  read  is  removed 
but  a  few  inches.     Light  is  the  agent  which  gives  to  this  sense 
its  wide  range.     The  nature  of  this  mysterious  force  is  not 
known,  and  it  is  not  here  to  be  discussed,  since  its  study 
belongs  more  properly  to  the  province  of  natural  philosophy. 

48.  It  is  sufficient,  in  this  connection,  to  state  that  the  theory 
of  light  now  generally  accepted,  and  which  best  explains  the 
facts  of  optics,  is  that  knowri  as  the  undulatory  theory.     This 
theory  supposes  that  there  exists  an  intangible,  elastic  medium, 
which  fills  all  space,  and  penetrates  all  transparent  substances, 
and  which  is  thrown  into   exceedingly  rapid  undulations  or 
waves,  by  the  sun  and  every  other  luminous  body  —  the  undu- 
lations being  propagated  with  extreme  rapidity,  and  moving 
not  less  than  186,000  miles  in  a  second. 

49.  These  waves  are  thought  to  produce  in  the  eye  the  sen- 
sation of  light,  in  the  same  manner  as  the  sonorous  vibrations 
of  the  air  produce  in  the  ear  the  sensation  of  sound.     That 
part  of  the  eye  which  is  sensitive  to  these  waves  is  the  expan- 
sion of  the  optic  nerve.    It  is  sensitive  to  no  other  impression 
than  that  of  light,  and  it  is  the  only  nerve  which  is  acted  upon 
by  this  agent.     The  optic  nerve,  also  called  the  "  second  pair  " 
of  cranial  nerves,  is  the  means  of  communication  between  the 
eye  and  the  brain. __ 

4T.  Sight  unlike  the  other  senses  ?    In  the  case  of  the  stars  ? 

48.  The  undulatory  theory  of  light  ?    What  does  the  theory  suppose  ? 

49.  The  sensation  of  light  ?    Optic  nerve  ? 


THE  SPECIAL  SENSES  287 

50.  The  two  nerves  constituting  the  pair  arise  from  ganglia 
lying  at  the  base  of  the  cerebrum  —  one  of  them  on  each  side 
—  from  which  points  they  advance  to  the  eyes,  being  united 
together  in  the  middle  of  their  course  in  the  form  of  the  letter 
X  (Fig.  57,  2).    By  this  union  the  two  eyes  are  enabled  to  act 
harmoniously, -and  in  some  respects  to  serve  as  a  double  organ. 
By  reason  of  this  same  intimate  nervous  communication,  when 
serious  disease  affects  one  eye,  the  fellow-eye  is  extremely 
liable  to  become  the  seat  of  sympathetic  inflammation ;  and  this, 
if  neglected,  almost  certainly  results  in  hopeless  blindness. 

51.  The  Organ  of  Sight — The  Eye.  — The  proximity  of  the 
eye  to  the  brain,  and  the  important  part  it  performs  in  giving 
expression  to  the  emotions,  have  given  it  the  name  of  "the 
window  of  the  soul."    The  exceeding  beauty  of  its  external 
parts,  and  the  high  value  of  its  function,  have  long  made  this 
organ  the  subject  of  enthusiastic  study.     It  is  chiefly  within 
the  last  twenty  years,  however,  that  this  study  has  been  suc- 
cessful and  fruitful  of  practical  results.     Several  ingenious 
instruments  have  been  invented  for  the  examination  of  the  eye 
in  health  and  disease,  and  new  operations  have  been  devised 
for  the  relief  of  blindness  and  of  impaired  vision.    As  u  result, 
it  is  now  a  well-marked  fact  that,  in  civilized  lands,  the  num- 
ber of  those  who  suffer  from  loss  of  sight  is  proportionally 
much  less  than  in  countries  where  science  is  less  known  and 
cultivated. 

52.  The  most  obvious  fact  in  respect  to  the  apparatus  of 
sight  is  that  there  are  two  eyes,  which  may  either  act  together 
as  one,  and  be  fixed  upon  one  object,  or  one  eye  may  be  used 
independently  of  the  other.     In  consequence  of  this  arrange- 
ment, the  loss  of  one  eye  does  not  necessitate  blindness,  and, 
in  fact,  it  not  infrequently  happens  that  the  sight  of  one  eye 
may  be  long  impaired  or  lost  before  the  fact  is  discovered. 
We  next  notice  that  the  eyes  are  placed  at  the  most  elevated 


50.  The  two  nerves  constituting  the  pair  of  nerves  ? 

51.  Why  is  the  eye  called  "  the  window  of  the  soul "  ?    Why  the  subject  of  enthusiastic 
study  ? 

52.  The  most  obvious  fact  ?    The  consequence  ?    The  next  thing  nottiff^f\  Jfe' 
Ytew  't    Of  what  does  the  organ  of  •vision  consist  ? 


UNIVERSITY  I 


288  THE  SPECIAL  SENSES 

part  of  the  body,  in  front,  and  near  the  brain.  They  also  com- 
mand a  wide  range  of  view,  being  moved  with  great  rapidity, 
and  "being  further  aided  by  the  free  motion  of  the  head  and 
neck.  The  organ  of  vision  consists  essentially  of  two  parts : 
the  optical  instrument  itself — the  eyeball  —  and  its  envelop- 
ing parts,  or  the  case  in  which  the  instrument  is  kept  free  from 
harm.  The  latter,  which  are  external,  and  which  we  shall  first 
consider,  are  chiefly  the  orbits,  the  eyelids,  and  the  apparatus 
for  the  tears. 

53.  The  Orbits.  —  The  eyeball,  which  is  a  delicate  organ,  is 
well  defended  against  external  injury  within  the  orbits  or  bony 
sockets  of  the  head.     These  are  deep  conical  hollows,  bounded 
in  part  by  the  bones  of  the  skull,  and  in  part  by  those  of  the 
nose  and  cheek.     The  orbit  juts  out  beyond  the  most  exposed 
portion  of  the  eyeball,  as  may  be  seen  by  laying  a  book  over 
the  eye,  when  it  will  be  found  that  no  part  of  the  eyeball, 
unless  it  be  very  prominent,  will  be  touched  by  the  book ;  so 
that  the  only  direction   in  which  an  injury  is  liable  to  be 
received  is  immediately  in  front  of  the  eye.     The  overhanging 
brow  is  itself  covered  by  a  layer  of  thick  skin,  studded  with 
short,  stout  hairs,  which  are  so  bent  as  to  prevent  the  perspira- 
tion from  running  into  the  eye  and  obscuring  vision.    Through 
a  hole  in  the  bottom  of  the  orbit,  the  nerve  of  sight  passes  out- 
ward from  the  brain.     The  orbit  also  contains  a  considerable 
amount  of  a  fatty  tissue,   upon  which,  as   upon  an  elastic 
cushion,  the  eye  rests. 

54.  The  Eyelids.  —  The  eyelids  are  two  movable  curtains,  or 
folds,  which,  when  shut,  cover  the  front  part  of  the  orbit,  and 
hide  the  eye  from  view.     The  upper  lid  is  the  larger,  has  a 
curved  margin,  and  moves  freely,  while  the  lower  lid  is  com- 
paratively short  and  straight,  and  has  but  a  slight  degree  of 
motion  (Fig.  63).     Skin  covers  the  exterior  of  the  lids,  while  a 
fine  mucous  membrane  lines  their  inner  surface,  and  is  likewise 
spread  out  over  the  entire  front  of  the  eyeball.    This  membrane, 

63.  The  protection  of  the  eyeball  against  injury  ?  The  overhanging  brow  ?  The  opening 
for  the  optic  nerve  ? 

54.  What  are  the  eyelids  ?  The  upper  lid  ?  The  lower  one  ?  The  mucous  membrane  of 
the  eye  ? 


THE  SPECIAL  SENSES 


289 


which  is  called  the  conjunctiva,  is  highly  sensitive,  and  thus 
plays  an  important  part  in  protecting  the  eye  against  the  lodg- 
ment of  sand,  ashes,  chaff, 
and  other  foreign  particles 
that  are  blown  about  in  the 
air.  This  sensitive  mem- 
brane will  not  endure  the 
presence  of  these  particles. 
If  any  dust  finds  access,  it 
causes  a  constant  winking, 
a  flow  of  tears,  and  other 
signs  of  irritation,  until  it 

FIG.    68.  —  FBONT   VIEW   OF   RIGHT   EYE.      jg  removed 
(Natural  Size) 

1.  The  Lachrymal,  or  tear  gland,  lying  be- 
neath the  upper  eyelid 

2.  The  Nasal  Duct  is  shown  by  the  dotted 
Inc.    The  *  marks  the  orifice  in  the  lower  lid 

The  central  black  spot  is  the  pupil;  sur- 
•oundiug  it  is  the  iris;  and  the  triangular 
rhite  spaces  are  the  visible  portion  of  the 


(Head  Note  8.) 

55.  The  long,  silky  eye- 
lashes, which  garnish  the 
edges  of  the  lids,  act  like  a 
sieve  to  prevent  the  entry  of 

eierotic  dust  and  other  irritants ;  and 

together  with  the  lids,  they 

egulate  the  amount  of  light  which  is  permitted  to  enter  the 
rye,  so  that  it  is  shielded  from  a  sudden  flood  or  glare  of  light. 
The  little  points  seen  in  the  figure  just  within  the  line  of  the 
lashes,  especially  on  the  lower  lid,  represent  the  mouths  of 
numerous  little  sebaceous  glands  (Fig.  64,  D,  D),  such  as  are 
always  found  in  the  neighborhood  of  hairs.  These  glands  sup- 
ply a  thick,  oily  material  which  greases  the  edges  of  the  lids 
and  prevents  their  adhering  together,  and  likewise  prevents 
the  overflow  of  the  tears  upon  the  cheek. 

8.  How  to  Remove  Foreign  Bodies  from  the  Eye. — "Lay  your 
finger  on  the  cheek,  and  draw  the  lower  lid  gently  down,  while  the  person 
looks  as  much  upward  as  possible,  and  we  shall  see  about  the  whole  ex- 
tent «r  the  lower  portion  of  the  conjunctiva,  and  thus,  if  any  foreign 
substance  is  there,  it  will  be  readily  detected,  and  easily  wiped  away  with 
a  folded  soft  rag  or  handkerchief.  Both  lids  have  a  piece  of  cartilage  in 
them  to  stiffen  them,  like  pasteboard,  and  keep  them  fitting  close  to  the 
eyeball.  The  upper  portion  of  this  conjunctival  sac  can  only  be  seen- by 
turning  over  the  upper  lid.  The  way  to  do  this  is  to  let  the  person  look 


65.  The  eyelashes  ?    The  little  points  within  the  line  of  the  lashes  ?     Of  what  use  are 
these  glands  ? 


290  THE  SPECIAL   SENSES 

56.  The  Lachrymal  Fluid,  or  the  Tears.  —  Just  within  the 
outer  part  of  the  bony  arch  of  the  brow,  where  the  bone  may 
be  felt  to  be  sharper  than  in  other  positions,  is  lodged  a  little 
organ  called  the  lachrymal  gland,  the  situation  of  which  is 
indicated  in  Fig.  63,  1.      This  is  the  gland  whence  flows  the 
watery  secretion,  commonly  called  the  tears,  which  is  designed 
to  perform  an  exceedingly  important  duty  in  lubricating  the 
lids,  and  in  keeping  the  exposed  surface  of  the  eyeball  moist 
and  transparent.     For,  without  this  or  some  similar  liquid,  the 
front  of  the  eye  would  speedily  become  dry  and  lustreless,  like 
that  of  a  fish  which  has  been  removed  from  the  water;  the 
simple  exposure  of  the  eye  to  the  air  would  then  suffice  to 
destroy  vision. 

57.  This  secretion  of  the  tears  takes  place  at  all  times, 
during  the  night  as  well  as  the  day ;  but  it  is  seldom  noticed, 
unless  when  under  the  influence  of  some  strong  mental  emo- 
tion—whether  of  sorrow  or  happiness  — it   is  poured  forth 
in  excess,  so  as  to  overflow  the  lids.     Strong  light  or  a  rapid 
breeze  will,  among  many  other  causes,  excite  the  flow  of  the 
tears.     That  portion  of  this  secretion  which  is  not  used  in 
moistening  the  eye  is  carried  off  into  the  nose  by  a  canal  situ- 
down  with  the  eyes  closed.     Taking  hold  of  the  lashes  with  one  hand, 
and  applying  a  pencil,  or  some  small,  round,  smooth  object,  over  the  lid 
above  the  globe,  we  lift  the  lashes  out  and  up,  warning  the  person  to  still 
keep  looking  down.     The  lid  will  suddenly  turn  over  with  a  little  spring 
from  the  bending  of  the  cartilage.     In  this  way  nearly  the  whole  of  the 
conjunctival  sac  will  be  exposed,  and  any  foreign  body  wiped  away,  as 
above  described.     But  suppose  no  friend  or  oculist  is  by  us  to  do  this. 
The  next  best  thing  is  to  take  hold  of  the  lashes  of  the  upper  lid,  and 
draw  it  forward  and  downward  over  the  lower  one,  blowing  the  nose 
violently  with  the  other  hand  at  the  same  time. 

"  If  the  foreign  substance  is  on  the  cornea,  take  a  strip  of  paper  not 
stiffer  than  ordinary  writing-paper,  about  a  quarter  of  an  inch  wide,  and 
roll  it  up  as  if  you  were  going  to  make  a  candle-lighter.  Look  at  the 
lower  end,  and  you  will  see  it  comes  to  a  point.  With  this  point  now  you 
may  safely  attempt  to  remove  any  foreign  substance  from  the  cornea. 
The  tears  which  will  flow  soften  the  paper,  and  prevent  injury  to  the 
delicate  covering  membrane  of  the  cornea."  —  Dr.  B.  Jay  Jeffries. 


56.  The  location  of  the  lachrymal  gland  ?    The  use  of  the  gland  ? 

57.  When  does  the  secretion  of  the  tears  occur  ?     The  secretion  not  used  for  the  eye  ? 
Location  of  the  nasal  duct  ?    Its  use  ?    The  overflow  of  tears  in  old  people  ? 


THE  SPECIAL  SENSES  291 

ated  near  the  inner  angle  of  the  eye,  called  the  nasal  duct. 
This  duct  is  shown  in  Fig.  63,  2,  and  is  connected  with  each 
lid  by  delicate  tubes,  which  are  indicated  by  dotted  lines  in 
the  figure ;  the  asterisk  marks  the  little  opening  in  the  lower 
lid,  by  which  the  tears  enter  the  nasal  duct.  By  gently  turn- 
ing the  inner  part  of  that  lid  downward,  and  looking  in  a  mir- 
ror, this  small  "  lachrymal  point "  may  be  seen  in  your  own 
eye.  In  old  people,  these  points  become  turned  outward,  and 
do  not  conduct  the  tears  to  the  nasal  cavity,  thus  causing  an 
overflow  of  tears  upon  the  face 

58.  Thus  we  observe  that  the  gland  which  forms  the  tears 
is  placed  at  the  outer  part  of  the  eye,  while  their  means  of 
exit  is. at  the  inner  angle  of  the  eye;  which  fact  renders  it 
necessary  that  this  watery  fluid  shall  pass  over  the  surface  of 
the  eyeball  before  it  can  escape.     This  arrangement  cannot  be 
accidental,  but  evinces  design,  as  it  thus  secures  the  perfect 
lubrication  of  the  surface  of  the  eye,  and  cleanses  it  from  the 
smaller  particles  of  dust  which  may  enter  it,  in  spite  of  the 
vigilance  of  the  lids  and  lashes.     The  act  of  winking,  which 
is  generally  unconsciously  performed,  and  which  takes  place 
six  or  more  times  in  a  minute,  assists  this  passage  of  the  tears 
across  the  eye,  and  is  especially  frequent  when  the  secretion 
is  most  abundant. 

59.  The  Eyeball. — The  eyeball,  or  globe  of  the  eye,  upon 
which  sight  depends,  is,  as  the  name  indicates,  spherical  in 
shape.     It  is  not  a  perfect  sphere,  since  the  front  part  projects 
somewhat  beyond  the  rest,  and  at  the  posterior  part  the  optic 
nerve  (Fig.  64,  N)  is  united  to  it,  resembling  the  junction  of 
the  stem  with  the  fruit.     In  its  long  diameter  —  that  is,  from 
side  to  side  —  it  measures  a  little  more  than  an  inch ;  in  other 
directions  it  is  rather  less  than  an  inch.     In  structure  the  ball 
of  the  eye  is  firm,  and  its  tense  round  contour  may  in  part  be 
felt  by  pressing  the  fingers  over  the  closed  lids. 

60.  The  eyeball  is  composed  chiefly  of  three  internal,  trans- 
parent media,  called  humors,  and  three  investing  coats,  or 

68.  The  watery  fluid  passing  over  the  eyeball  ?   Design  of  the  arrangement  ?   Winking  ? 

69.  Describe  the  shape  of  the  eyeball.     Its  structure. 
60.   Of  what  is  the  eyeball  composed  ?    State  how. 


292 


THE  SPECIAL  SENSES 


tunics.  The  former  are  the  aqueous  humor,  Fig.  64,  A,  the 
crystalline  lens  L,  and  the  vitreous  humor  v.  Of  these  the  lens 
alone  is  solid.  The  three  coats  of  the  eyeball  are  called  the 
sclerotic  s,  the  choroid  Ch,  and  the  retina  R.  This  arrangement 
exists  in  respect  to  five-sixths  of  the  globe  of  the  eye,  but  in 
the  anterior  one-sixth,  these  coats  are  replaced  by  the  cornea  c, 
which  is  thin  and  transparent,  so  that  the  rays  of  light  pass 
freely  through  it,  as  through  a  clear  window-pane. 

61.   In  shape,  the  cornea  is  circular  and  prominent,  resem- 
bling a  miniature  watch-glass,  about  -^  of  an  inch  thick.     In 


FIG.  64.  —  VERTICAL  SECTION  OF  THE  EYE     (Enlarged ) 


C,  The  Cornea 

A,  The  Aqueous  Humor 
I,  The  Iris 

P,  The  Pupil 

L,  The  Crystalline  Lens 

H,  The  Ligament  of  the  Lens 

B,  The  Ciliary  Process 

V,  The  Cavity  containing  the  Vitreous  Humor 
S,  The  Sclerotic 


Ch,  The  Choroid 

B,  The  Retina 

N,  The  Optic  Nerve 

DD,  The  Eyelids 

X,  The    Levator    Muscle    of    the 

Lid 
Y,  The    Upper    Straight   Muscle   of    the 

Eye 
Z,  The  Lower  Straight  Muscle 


Upper 


structure,  it  resembles  horn  (as  the  name  signifies),  or  the  nail 
of  the  finger,  and  is  destitute 'of  blood-vessels.     The  sclerotic 


61.  The  shape  of  the  cornea  ?    Its  structure  ?    The  "  white  of  the  eye  "  ? 


THE  SPECIAL  SENSES  293 

(from  scleros,  hard)  is  composed  of  dense,  white  fibrous  tissue, 
and  gives  to  the  eyeball  its  firmness  of  figure  and  its  white 
color ;  in  front,  it  constitutes  the  part  commonly  called  "  the 
white  of  the  eye."  It  is  one  of  the  strongest  tissues  in  the 
body.  It  possesses  very  few  vessels,  and  is  not  very  sensitive. 
It  affords  protection  to  the  extremely  delicate  interior  parts 
of  the  eye,  and  the  little  muscles  which  effect  its  movements 
are  inserted  into  the  sclerotic  a  short  distance  behind  the 
cornea  (see  Fig.  64,  Y,  z).  It  is  perforated  posteriorly  to 
admit  the  optic  nerve. 

62.  The  choroid  is  the  second  or  middle  coat  of  the  eyeball, 
and  lies  closely  attached  to  the  inner  surface  of  the  sclerotic. 
Unlike  the  latter,  its  structure  is  soft  and  tender;  it  is  dark 
in  color,  and  possesses  a  great  abundance  of  blood-vessels.  Its 
dark  color  is  due  to  a  layer  of  dark  brown  or  chocolate-colored 
cells  spread  out  over  its  inner  surface.  This  dark  layer  serves 
to  absorb  the  rays  of  light  after  they  have  traversed  the  trans- 
parent structures  in  front  of  it.  If  the  rays  were  reflected 
from  side  to  side  within  the  eye,  instead  of  being  thus  absorbed, 
confused  vision  would  result  from  the  multitude  of  images 
which  would  be  impressed  upon  the  optic  nerve. 

60.  This  mechanism  has  been  unconsciously  imitated  by  the 
opticians,  who,  when  they  make  a  microscope  or  telescope,  take 
care  that  the  interior  of  its  tube  shall  be  coated  with  a  thick 
layer  of  black  paint  or  lamp-black ;  for  without  it,  a  clear 
delineation  of  the  object  to  be  viewed  is  impossible.  The 
albinos,  in  whom  these  dark  cells  of  the  choroid  are  wanting, 
have  imperfect  vision,  especially  in  the  daytime  and  in  strong 
lights.  The  dark  cells  are  also  wanting  in  white  rabbits, 
and  other  animals  that  have  red  or  pink  eyes;  their  vision 
appears  to  be  imperfect  in  the  presence  of  a  bright  light. 

64.  The  Iris. — Continuous  with  the  choroid,  in  the  front 
part  of  the  globe  of  the  eye,  is  a  thin,  circular  curtain,  which 


62.  The  second  or  middle  coat  of  the  eyeball  ?    Its  dark  color  ? 

68.   Similar  mechanism  in  microscopes  ?    The  albinos  ?    White  rabbits  ? 

64.  What  is  the  iris  ?    Its  construction  ?    How  is  the  size  of  the  pupil  regulated  ? 


294 


THE  SPECIAL  SENSES 


FIG.  65.  —  FRONT  SECTION  OF  THE  EYEBALL, 
VIEWED  FROM  BEHIND,  AND  SHOWING  SlJS- 
PENSORY  LIGAMENT,  IRIS,  AND  PUPIL 


occasions  the  brown,  blue,  or  gray  color  of  the  eye  in  different 
individuals.  On  account  of  the  varieties  of  its  color,  this 
membrane  has  received  the 
name  Iris,  which  is  the 
.  Greek  word  for  "  rainbow  " 
(see  Fig.  64,  i).  A  front 
view  of  it  is  shown  in  Fig. 
63.  The  iris  is  pierced  in 
its  centre  by  a  round  open- 
ing, called  the  pupil  (P), 
which  is  constantly  vary- 
ing in  size.  In  olden  times 
it  was  spoken  of  as  the 
"apple  of  the  eye."  The 
hinder  surface  of  the  iris, 
except  in  albinos,  has  a 
layer  of  dark  coloring  mat- 
ter resembling  that  of  the 
choroid.  The  iris  is  a  muscular  organ,  and  contains  two 
distinct  sets  of  fibres,  one  of  which  is  circular,  while  the 
other  radiates  outward  from  the  pupil.  Their  action  regulates 
the  size  of  the  pupil ;  for  when  the  circular  set  acts,  the  open- 
ing contracts.  Their  action  is  involuntary,  and  depends  on 
the  reflex  system  of  nerves,  which  causes  the  contraction  of 
the  pupil  when  a  strong  light  falls  upon  the  eye,  and  its  expan- 
sion when  the  illumination  is  feeble.  The  suspensory  ligament 
holds  the  crystalline  lens  in  its  place.  (Fig.  65.) 

65.  The  iris,  accordingly,  serves  a  very  useful  purpose  in 
regulating  the  admission  of  light  to  the  eye  (see  Fig.  65).  It, 
however,  does  not  act  instantaneously ;  and  hence,  when  we 
pass  quickly  from  a  dark  room  into  the  bright  sunlight,  the 
vision  is  at  first  confused  by  the  glare  of  light,  but  as  soon  as 
the  pupil  contracts,  the  ability  to  see  becomes  perfect.  On  the 
other  hand,  when  we  enter  a  dark  apartment,  Such  as  a  cellar, 
for  a  short  time  we  can  see  nothing  clearly ;  but  as  soon  as  the 


65.  The  admission  of  light  to  the  eye  ?    The  action  of  the  iris  under  different  "'-«nm- 
stances  ?    The  lustre  of  the  eye,  how  affected  in  youth  and  old  age  ? 


THE  SPECIAL  SENSES  295 

pupil  expands  and  admits  more  light,  we  are  enabled  to  distin- 
guish the  surrounding  objects.  Animals  of  the  cat  species, 
and  others  which  prowl  around  after  nightfall,  are  enabled  to 
see  in  the  dark  by  having  the  iris  very  dilatable.  The  size  of 
the  pupil  affects  the  lustre  of  the  eye.  When  it  is  large,  as  it 
usually  is  during  youth,  the  eye  appears  clear  and  brilliant ; 
while  in  old  age  the  pupil  is  small  and  the  eye  is  dull.  The 
brilliancy  of  the  eye  -is  in  part,  at  least,  dependent  upon  the 
reflection  of  light  from  the  front  surface  of  the  crystalline 
lens. 

66.  Certain  poisonous  vegetables  have  the  property  of  caus- 
ing the  pupil  to  dilate,  and  have  been  used  in  small  doses  to 
increase  the  beauty  of  the  eye.     One  of  these  drugs  has  been 
so  largely  used  by  the  ladies  for  this  purpose  that  it  has 
received  the  name  belladonna,  from  the  Italian  words  meaning 
"  beautiful  lady."     This  hazardous  practice  has  resulted  more 
than  once  in  the  death  of  the  person  desiring  thus  to  increase 
her  personal  attraction.     The  common  English  name  for  bella- 
donna is  "  deadly  nightshade."     (In  the  diagram  on  page  303 
the  shape  and  relations  of  the  iris  are  more  accurately  shown 
than  in  the  figures  referred  to  above.) 

67.  The  Retina  constitutes  the  third  and  inner  coat  of  the 
globe  of  the  eye.     This,  the  important  part  of  the  eye  that  is 
sensitive  to  light,  is  a  kind  of  nervous  membrane,  formed  by 
the  expansion  of  the  optic  nerve.     Its  texture  is  soft,  smooth, 
and  very  thin ;  it  is  translucent  and  of  an  opaline,  or  grayish- 
white  color.     It  is  sensitive  to  light  alone ;  and  if  any  form  of 
mechanical  irritation  be  applied  to  it,  the  sensations  of  touch 
and  pain  are  not  experienced,  but  flashes  of  fire,  sparks,  and 
other  luminous  appearances  are  perceived.     Thus  an  electric 
shock  given  to  the  eyeball  occasions  a  flash  of  light;  and  a 
sudden  fall,  or  a  blow  upon  the  eye,  is  often  apparently  accom- 
panied by  the  vision  of  "  stars." 

68.  These  phenomena  are  due  to  what  is  termed  the  "  specific 

66.  Means  used  to  increase  the  beauty  of  the  eye  ?    The  injurious  consequences  ? 

67.  What  part  does  the  retina  constitute  ?    How  formed  ?    Its  texture  ?    Color  ?    Senst 
tiveness  ? 

68.  Specific  energy  of  the  optic  nerve  ?    Trial  in  Germany  f 


296  THE  SPECIAL  SENSES 

energy  "  of  the  optic  nerve,  which  nerve,  in  common  with  the 
other  nerves  of  the  special  sense,  obeys  a  general  law  of  nature, 
which  requires  that,  whenever  one  of  these  nerves  is  stimulated, 
it  shall  respond  with  the  sensation  peculiar  to  itself.  These 
flashes  of  retinal  light  have  no  power  to  illuminate  external 
objects,  although  the  opposite  of  this  statement  has  been  main- 
tained. On  the  occasion  of  a  remarkable  trial  in  Germany,  it 
was  claimed  by  a  person  who  had  been  severely  assaulted  on  a 
very  dark  night,  that  the  flashes  of  light  caused  by  repeated 
blows  upon  the  head  enabled  him  to  see  with  sufficient  distinct- 
ness to  recognize  his  assailant.  But  the  evidence  of  scientific 
men  entirely  refuted  this  claim,  by  pronouncing  that  the  eye, 
under  the  circumstances  named,  was  incapacitated  for  vision. 
Too  intense  light  occasions  a  feeling  of  pain,  but  it  is  of  a 
peculiar  kind,  and  is  termed  "  dazzling." 

69.  All  parts  of  the  retina  are  not  equally  sensitive,  and 
singularly  enough,  the  point  of  entry  of  the  nerve  of  sight  in 
the  back  part  of  the  eyeball  is  entirely  insensible  to  light,  and 
is  called  the  "  blind  spot."  The  existence  of  this  point  rmay 
be  proved  by  a  simple  experiment.  Hold  the  accompanying 
figure,  on  page  283,  directly  in  front  and  parallel  with  the  eyes. 


FIG.  66 

Close  the  left  eye,  and  fix  the  sight  steadily  on  the  left-hand 
circle ;  then,  by  gradually  varying  the  distance  of  the  figure 
from  the  eye,  at  a  certain  distance  (about  six  inches),  the  right- 
,hand  circle  will  disappear,  but  nearer  or  further  than  that,  it 
will  be  plainly  seen.  The  other  eye  may  be  also  tried,  with  a 
similar  result :  if  the  gaze  be  directed  to  the  right-hand  circle, 
the  left  one  will  seem  to  disappear.  The  experiment  may  be 

69.   Sensitiveness  of  all  parts  of  the  retina  ?    Experiment  to  prove  the  existence  of  the 
"blind  spot"? 


THE  SPECIAL  SENSES  297 

repeated  by  using  two  black  buttons  on  the  marble  top  of  a 
bureau,  or  on  some  other  white  surface.  The  blind  spot  does 
not  practically  interfere  with  vision,  since  the  eye  is  seldom 
fixed  immovably  on  an  object,  and  the  insensitive  parts  of  the 
two  eyes  can  never  be  directed  upon  the  same  object  at  the 
same  time. 

70.  Impressions  made  upon  the  retina  are  not  at  once  lost, 
but  continue  a  measurable  length  of  time,  and  then  gradually 
fade  away.     Thus,  a  bright  light,  or  color,  gazed  at  intently, 
cannot  be  immediately  dismissed  from  sight  by  closing  or  turn- 
ing away  the  eyes.     A  stick  lighted  at  one  end,  if  whirled 
around  rapidly  in  the  dark,  presents  the  appearance  of  an  un- 
broken luminous  ring;  and  the  spokes  of  a  rapidly  revolving 
carriage-wheel  seem  to  be  merged  into  a  plane  surface.     If  an 
object  move  too  rapidly  to  produce  this  sort  of  lasting  impres- 
sion, it  is  invisible,  as  in  the  case  of  a  cannon-ball  passing 
through  the  air  in  front  of  us. 

71.  If  a  card,  painted  with  two  primary  colors  —  as  red  and 
yellow  —  be  made  to  rotate  swiftly,  the  eye  perceives  neither 
of  them  distinctly ;  but  the  card  appears  painted  with  their 
secondary  color  —  orange.      The  average  duration  of  retinal 
images  is  estimated  at  one-eighth  of  a  second ;  and  it  is  because 
they  thus 'endure,  that  the  act  of  winking,  which  takes  place 
so  frequently,  but  so  quickly,  is  not  noticed  and  does  not  inter- 
rupt the  vision.     The  retina  is  easily  fatigued  or  deprived  of 
its  sensibility.     After  looking  steadfastly  at  a  bright  light,  or 
at  a  white  object  on  a  black  ground,  a  dark  spot  corresponding 
in  shape  to  the  bright  object,  presents  itself  in  whatever  direc- 
tion we  look.    This  spot  passes  away  as  the  retina  resumes  its 
activity. 

72.  If  a  bright  color  be  gazed  at  intently,  and  the  eyes  then 
be  turned  to  a  white  surface,  a  spot  will  appear ;  but  its  color 
will  be  the  complement  of  that  of  the  object.     Fix  the  eye 
upon  a  red  wafer  upon  a  white  ground,  and  on  removing  the 

70.   Duration  of  impressions  upon  the  retina  ?    How  illustrated  ? 

Tl.   What  further  illustration?    Winking,  why  it  is  not  noticed  ?    Ease  with  which  the 
retina  is  fatigued  or  deprived  of  sensibility  ?    How  shown  ? 

72.  How  further  shown  ?    How  is  the  result  accounted  for  ?    "  Color-blindness  "  ? 


298  THE  SPECIAL  SENSES 

wafer  a  greenish  spot  of  the  same  shape  takes  its  place.  This 
result  happens  because  a  certain  portion  of  the  retina  has 
exhausted  its  power  to  perceive  the  red  ray,  and  perceives  only 
its  complementary  ray,  which  is  green.  The  color  thus  sub- 
stituted by  the  exhausted  retina  is  called  a  physiological  or 
accidental  color.  In  some  persons  the  retina  is  incapable  of 
distinguishing  different  colors,  when  they  are  said  to  be  affected 
with  "  color-blindness.''  Thus,  red  and  green  may  appear  alike, 
and  then  a  cherry-tree,  full  of  ripe  fruit,  will  seem  of  the  same 
color  in  every  part.  Eailroad  accidents  have  occurred  because 
the  engineer  of  the  train,  who  was  color-blind,  has  mistaken  the 
color  of  a  signal.  (Head  Note  9.) 

73.  The  Crystalline  Lens. — Across  the  front  of  the  eye,  just 
behind  the  iris,  is  situated  the  crystalline  lens,  enclosed  within 
its  own  capsule.  It  is  supported  in  its  place  partly  by  a  deli- 
cate circular  ligament,  and  partly  by  the  pressure  of  adjacent 
structures.  It  is  colorless  and  perfectly  transparent,  and  has 
a  firm  but  elastic  texture.  In  shape,  it  is  doubly  convex,  and 
may  be  rudely  compared  to  a  small  lemon-drop.  The  front 
face  of  the  lens  is  flatter  than  the  other,  and  is  in  contact  with 
the  iris  near  its  pupillary  margin,  as  is  represented  in  the  dia- 
gram of  page  290.  It  is  only  one-fourth  of  an  inch  thick. 

9.  Color-blindness.  —  "Daltonism,  or  color-blindness,  receives  its 
name  from  the  eminent  English  chemist  who  described  this  infirmity 
as  it  existed  in  his  own  case.  ,  It  arises  from  an  unnatural  condition 
of  the  organs  of  vision  which  prevents  the  discrimination  of  certain 
colors.  Some  persons  will  mistake  red  for  green  ;  so  that  ripe  cherries  on 
a  tree  appear  the  same  as  the  leaves;  others  recognize  only  black  and 
white.  Persons  thus  affected  are  sometimes  incapable  of  discriminating 
musical  tones.  The  healthy  eye  ordinarily  fails  to  discriminate  between 
certain  colors,  blue  and  green  especially,  when  viewed  by  artificial 
light.  But  even  this  may  in  a  measure  be  overcome  by  training,  so 
that  an  expert  dealer  in  siik  obtains  a  knowledge  of  the  shades  of  blue, 
green,  and  violet,  which  is  proof  against  the  confusing  influence  of  gas- 
light and  tinted  curtains.  The  eyes  of  persons  who  have  much  to  do  with 
colors  are  more  liable  to  become  overstrained  than  those  dealing  chiefly 
with  rays  of  white  light." — Flint's  Physiology  (in  part}. 


73.  The  location  of  the  crystalline  lens  ?     How  supported  ?     Its  color  and  texture  ? 
Shape?    Size? 


THE  SPECIAL  SENSES  299 

74.  When  this  little  body  becomes  opaque,  and  no  longer 
affords  free  passage  to  the  rays  of  light,  as  often  happens  with 
the  advance  of  age,  an  affection  termed  "  cataract "  is  produced. 
Between  the  crystalline  lens  and  the  cornea  is  a  small  space 
which  contains  the  aqueous  humor  (see  Fig.  64,  A).    This  humor 
consists  of  five  or  six  drops  of  a  clear,  colorless  liquid  very 
much  like  water,  as  its  name  implies.     That  part  of  the  globe 
of  the  eye  lying  behind  the  lens  is  occupied  by  the  vitreous 
humor,  so  called  from  its  fancied  resemblance  to  melted  glass 
(Fig.  64,  v).     This  humor  is  a  transparent,  jelly-like  mass, 
enclosed  within  an  exceedingly  thin  membrane.     It  lies  very 
closely  applied  to  the  retina,  or  nervous  membrane  of  the  eye, 
and  constitutes  fully  two-thirds  of  the  bulk  of  the  eyeball. 

75.  The  Uses  of  the  Crystalline  Lens.  —  A  convex  lens  has  the 
property  of  converging  the  rays  of  light  which  pass  through  it; 
and  the  point  at  which  it  causes  them  to  meet  is  termed  its 


FIG.  67.  — THE  RETINAL  IMAGE 

focus.  If  a  lens  of  this  description,  such  as  a  magnifying  or 
burning-glass,  be  held  in  front  of  an  open  window,  in  such  a 
position  as  to  allow  its  focus  to  fall  upon  a  piece  of  paper,  it 
will  be  found  to  depict  upon  the  paper  a  miniature  image  of  the 
scene  outside  of  the  window.  It  will  be  further  noticed  that 
the  image  is  inverted,  or  upside  down,  and  that  the  paper  at 
the  place  upon  which  the  image  is  thrown  is  much  brighter 
than  any  other  part. 

74.  Cataract  ?    Aqueous  humor  ?    Vitreous  humor  f 

75.  What  is  a  lens  and  its  focus  ?    The  miniature  image,  how  produced  ? 


300  THE  SPECIAL  SENSES 

76.  Now  all  the  transparent  structures  of  the  eye,  but  es- 
pecially the  crystalline  lens,  operate  upon  the  retina,  as  the 
convex  lens  acts  upon  the  paper  —  that  is,  they  paint  upon  the 
retina  a  bright,  inverted  miniature  of  the  objects  that  appear  in 
front  of  the  eye  (Fig.  67).     That  this  actually  takes  place  may 
be  proved  by  experiment.     If  the  eyeball  of  a  white  rabbit,  the 
walls  of  which  are  transparent,  be  examined  while  a  lighted 
candle  is  held  before  the  cornea,  an  image  of  the  candle-flame 
may  be  seen  upon  the  retina. 

77.  The  form  and  structure  of  the  crystalline  lens  endow  it 
with  a  remarkable  degree  of  refractive  power,  and  enable  it  to 
converge  all  the  rays  of  light  that  enter  it  through  the  pupil, 
to  a  focus  exactly  at  the  surface  of  the  retina.     When  this  lens 
is  removed  from  the  eye,  as  is  frequently  done  for  the  cure  of 
cataract,  it  is  found  that  the  rays  of  light  then  have  their  focus 
three-eighths  of  an  inch  behind  the  retina ;  that  the  image  is 
four  times  larger  than  in  the  healthy  eye ;  that  it  is  less  bril- 
liant, and  that  its  outline  is  very  indistinct.     From  this  we 
learn  that  one  of  the  uses  of  the  crystalline  lens  is  to  make  the 
retinal  image  bright  and  sharply  denned,  at  the  same  time  that 
it  reduces  its  size.     Indeed,  the  small  size  of  the  image  is  a 
great  advantage,  as  it  enables  the  limited  surface  of  the  retina 
to  receive,  at  a  glance,  impressions  from  a  considerable  field  of 
vision. 

78.  As  the  image  upon  the  retina  is  inverted,  how  does  the 
mind  perceive  the  object  in  its  true,  erect   position?     Many 
explanations  have  been  advanced,  but  the  simplest  and  most 
satisfactory  appears  to  be  found  in  the  fact  that   the  retina 
observes  no  difference,  so  to  speak,  between  the  right  and  left 
or  the  upper  and  lower  positions  of  objects.     In  fact,  the  mind 
is  never  conscious  of  the  formation  of  a  retinal  image,  arid 
until   instructed,   has   no   knowledge   that  it   exists.     Conse- 
quently, our  knowledge  of  the  relative  location  of  external 
objects  must  be  obtained  from  some  other  source  than  the  ret- 


76.  How  are  figures  painted  upon  the  retina  ?    How  proved  ? 

77.  What  can  be  said  in  respect  to  the  form  and  structure  of  the  crystalline  lens  ? 

78.  How  is  the  inverted  image  upon  the  retina  presented  in  its  true  position  to  the  mind  ? 


THE  SPECIAL  SENSES  301 

ina.  The  probable  source  of  this  knowledge  is  the  habitual 
comparison  of  those  objects  with  the  position  of  our  own 
bodies ;  thus,  to  see  an  elevated  object,  we  know  we  must  raise 
the  head  and  eyes ;  and  to  see  one  at  our  right  hand,  we  must 
turn  the  head  and  eyes  to  the  right. 

79.  Long-sight  or  Hyperopia,  and  Short-sight  or  Myopia. — 
The  eye  is  not  in  all  cases  perfectly  formed.     I^or  example, 
persons  may  from  birth  have  the  cornea  too  prominent  or  too 
flat,  or  the  lens  may  be  too  thick  or  too  thin.     In  either  of 
these  conditions  sight  will  be  more  or  less  defective  from  the 
first,  and  the  defect  will  not  tend  to  disappear  as  life  advances. 
The  most  common  imperfection,  however,  is  in  the  shape  of 
the  globe ;  which  may  be  short  (Fig.  68,  H),  as  compared  with 
the  natural  eye,  N,  or  it  may  be  too  long,  M. 

80.  When  the  globe-is  short,-  only  objects  that  are  at  a 
distance  can  be  clearly  seen,  and  the  condition  of  the  vision  is 
known  as  "  lonfi-sight."  or  hyperopia.     It  will  be  observed,  by 


FIG.  68. —THE  DIFFERENT  SHAPES  OF  THE  GLOBE  OF  THE  EY* 

N,  The  Natural  Eye  M,  The  Short-sighted  Eye 

H,  The  Long-sighted  Eye  8,  Parallel  Rays  from  the  Sun 

reference  to  Fig.  68,  that  the  focus  of  the  rays  of  light  would 
fall  behind  the  retina  of  this  eye.  When  the  globe  is  too  long, 
only  objects  that  are  very  near  to  the  eye  can  be  clearly  seen, 
and  the  condition  resulting  from  this  defect  is  termed  "  short- 
sight,"  or  myopia.  The  focus  of  the  rays  of  light  is,  in  this 
case,  formed  in  the  interior  of  the  eye  in  front  of  the  retina. 

79.  The  uniform  perfection  of  the  eye  ?    Examples  ?    The  most  common  imperfection  ? 

80.  How  is  "  long-sight "  explained  ?    "  Short-sight "  f 

' 

If  Am 


302  THE  SPECIAL  SENSES 

81.  Long-sight,  or  hyperopia,  is  common  among  school-chil- 
dren,  nearly   as   much  so   as   short-sight,   and   must   not  be 
confounded  with  the  defect  known  as  the  "far-sight"  of  old 
people ;  although  in  both  affections  the  sight  is  improved  by 
the  use  of  convex  glasses.     Children  not  infrequently  discover 
that  they  see  much  better  when  they  chance  to  put  on  the 
spectacles  of  old  persons.     For  the  relief  of  short-sight,  con- 
cave glasses  should  be  employed ;  as  they  so  scatter  the  rays 
of  light  as  to  bring  the  focus  to  the  retina,  and  thus  cause  the 
vision  of  remote  objects  to  become  at  once  distinct.    That  form 
of  "  squint,"  in  which  the  eyes  are  turned  inward,  is  generally 
dependent  upon  long-sight,  while  that  rarer  form,  when  they 
turn  outward,  is  due  to  short-sight.     (Bead  Note  10.) 

82.  The    Function    of    Accommodation. — If,    after    looking 
through  an  opera-glass  at  a  very  distant  object,  it  is  desired 
to  view  another  nearer  at  hand,  it  will  be  found   impossible 
to  obtain  a  clear  vision  of  the  second  object  unless  the  adjust- 
ment of  the  instrument  be  altered,  which  is  effected  by  means 
of  the  screw.     If  an  object,  like  the  end  of  a  pencil,  be  held 
near  the  eye,  in  a  line  with  another  object  at  the  other  side  of 

10.  On  the  Production  of  Short-Sight.  —  "The  observations  of  Conn 
in  the  schools  and  University  of  Breslau,  of  Kruger  in  Frankfort-on-the- 
Main,  of  Erismann  in  St.  Petersburgh,  of  Von  Hoffmann  in  Wiesbaden, 
and  others  abroad,  prove  most  conclusively  that  one  of  the  bad  effects  of 
school  and  college  life  is  to  produce  diseases  of  the  eyes.  They  have 
shown  that  near-sightedness  increases  rapidly  in  frequency  as  you  go  up 
in  the  scale  of  schools  from  the  primaries  of  the  rural  districts  to  the 
universities.  The  gravity  of  this  finding  may  be  appreciated  when  we 
remember  that  near-sightedness  is  a  disease,  and  that  it  very  frequently 
descends  from  one  generation  to  another,  marked  by  such  organic  changes 
in  the  eyes  as  tend  to  the  production  of  the  worst  forms  of  the  malady, 
and  to  blindness.  In  1867,  Cohn,  of  Breslau,  published  the  results  of  the 
examination  of  the  eyes  of  10,060  scholars.  His  examinations  covered 
the  entire  range  of  school  life.  He  found  that  1,750  of  the  10,060  children 
had  defective  vision  —  about  seventeen  per  cent.  He  also  examined, 
without  selection,  410  of  the  964  students  of  the  Breslau  University,  and 
found  that  not  one-third  had  normal  eyes."  — Dr.  C.  It.  Agnew. 


81.  Long-sight,  how  common  ?    With  what  must  it  not  be  confounded  ?    Kind  of  glasses 
for  short-sight  ?    Why  ?    Squint  ? 

82.  What  is  stated  in  connection  with  the  opera-glass  ?    Experiment  with  pencil  and  dis- 
tant object  ? 


THE  SPECIAL  SENSES  303 

the  room,  or  out  of  the  window,  and  the  eye  be  fixed  first 
upon  one  and  then  upon  the  other,  it  will  be  found  that  when 
the  pencil  is  clearly  seen,  the  further  object  is  indistinct;  and 
when  the  latter  is  seen  clearly,  the  pencil  appears  indistinct, 
and  that  it  is  impossible  to  see  both  clearly  at  the  same  time. 
Accordingly,  the  eye  must  have  the  capacity  of  adjusting  itself 
to  distances,  which  is  in  some  manner  comparable  to  the  action 
of  the  screw  of  the  opera-glass. 

83.  This,  which  has  been  called  the  function  of  accommoda- 
tion, is  one  of  the  most  admirable  of  all  the  powers  of  the 
eye,  and  is  exercised  by  the  crystalline  lens.  It  consists 
essentially  in  a  change  in  the  curvature  of  the  front  surface 
of  the  lens,  partly  through  its  own  elasticity,  and  partly 
through  the  action  of  the  ciliary  muscle.  When  the  eye  is 
at  rest- — that  is,  when  accommodated  for  a  distant  object — 


FIG.  69. — THK  FUNCTION  OF  ACCOMMODATION 

The  nght  half  of  the  diagram  shows  the  eye  at  rest.    The  left  half  shows  the  lens 
accommodated  for  near  vision 

the  lens  is  flatter  and  its  curvature  diminished  (see  Fig.  69) ; 
but  when  strongly  accommodated  for  near  vision,  the  lens 
becomes  thicker,  its  curvature  increases,  and  the  image  on 
the  retina  is  made  more  sharp  and  distinct.  Since  a  strong 
light  is  not  required  in  viewing  near  objects,  the  pupil  con- 
tracts, as  is  shown  in  the  left-hand  half  of  the  diagram. 

83.    Function  of  accommodation ?     In  what  does  it  consist?     How  is  the  function 
explained  ? 


304  THE  SPECIAL  SENSES 

84.  Old-sight,  or  Presbyopia.  —  But  this  marvellously  beauti- 
ful mechanism  becomes  worn  with  use ;  or,  more  strictly  speak- 
ing, the  lens,  like  other  structures  of  the  body,  becomes  harder 
with  the  approach  of  old  age.     The  material  composing  the 
lens  becomes  less  elastic,  the  power  to  increase  its  curvature  is 
gradually  lost,  and  as  a  consequence,  the  person  is  obliged  to 
hold  the   book   farther   away  when   reading,  and   to   seek   a 
stronger   light.      In  a  word,  the   function  of  accommodation 
begins  to  fail,  and  is  about  the  first  evidence  that  marks  the 
decline  of  life.     By  looking  at  the  last  preceding  diagram,  and 
remembering  that  the  increased  curvature  of  the  lens  cannot 
take  place,  it  will  be  at  once  understood  why  old-sight  is  bene- 
fited in  near  vision  by  the  convex  lens,  such  as  the  spectacles 
of  old  people  contain.     It  acts  as  a  substitute  for  the  deficiency 
of  the  crystalline  lens.     (Head  Note  11.) 

85.  Astigmatism.  —  It  often  happens  that  the  curvature  of 
the  cornea  or  of  the  crystalline  lens,  or  of  both,  is  not  uniform. 
This  is  more  often  true  of  the  cornea  than  of  the  crystalline 
lens.     When  this  happens,  rays  of  light  which  pass  through 
that  portion  of  the  cornea  (or  lens)  having  a  greater  curvature, 
will  be  refracted  to  a  focus  more  quickly  than  the  rest.     Under 
such  circumstances  the  focus  will  not  be  a  point,  as  it  should 
be  for  perfect  vision,  but  a  line.     Such  an  eye  is  astigmatic. 
This   difficulty  is  very  common,  and  should  be  corrected  by 
glasses  fitted  for  each  case. 

11.  The  Choice  of  Glasses.  —  "The  perfectly  healthy,  normal  eye 
begins  to  need  a  glass  for  ordinary  work  at  between  forty  and  forty-five 
years  of  age  —  of  course,  we  here  exclude  all  debilitated  conditions  of  the 
body  resulting  from  disease.  Now,  then,  comes  the  question  —  shall  we 
put  on  glasses,  and  of  what  strength  ?.  To  answer  some  prevalerit  fallacies 
handed  down  from  one  generation  to  another,  we  cannot  do  better  than 
quote  from  the  highest  authority,  Prof.  Donders,  who  says :  '  The  opinion 
is  rather  general  that  we  should  refrain  as  long  as  possible  from  the  use 
of  convex  glasses.  But,  is  it  not  folly  to  weary  the  eyes  and  the  mind 
together,  without  necessarily  condemning  ourselves  to  guess,  with  much 
trouble,  at  the  forms  which  we  could  see  pretty  well  with  glasses  ? ' 

"Strangely  enough,  people  have  fallen  also  into  the  opposite  fault. 


84.  Change  of  sight  with  the  approach  of  old  age  ?    Explain  the  change. 

85.  Astigmatism  ?    Its  cure  ? 


THE  SPECIAL  SENSES  305 

86.  The  Sense  of  Hearing  —  Sound.  —  Hearing  is  the  special 
sense  by  means  of  which  we  are  made  acquainted  with  sound. 
What  is  sound  ?     It  is  an  impression  made  upon  the  organs  of 
hearing,  by  the  vibrations  of  elastic  bodies.     This  impression 
is  commonly  propagated  by  means  of  the  air,  which  is  thrown 
into  delicate  undulations  in  all  directions  from  the  vibrating 
substance.     When  a  stone  is  thrown  into  smooth  water,  a  wave 
of  circular  form  is  set  in  motion  from  the  point  where  the 
stone. struck,  which,  as  it  advances,  constantly  increases  in  size 
and  diminishes  in  force. 

87.  Somewhat  resembling  this  is  the  undulation,  or  sound- 
wave,  which  is   imparted   by   a   sonorous   vibration    to    the 
surrounding  atmosphere.     Its   shape,   however,   is   spherical, 
rather  than  circular,  since  it  radiates  upward,  downward,  and 
obliquely,  as  well   as   horizontally,  like  the   wave  in  water. 
The  rate  of  motion  of  this  spherical  wave  of  air  is  about  1050 
feet  per  second,  or  one  mile  in  five  seconds.     In  water,  sound 
travels   four  times   as  fast  as  in  air,  and  still  more  rapidly 
through  solid  bodies;  along  an  iron  rod  its  velocity  is  equal 
to  two  miles  per  second. 

88.  The  earth,  likewise,  is  a  good  conductor  of  sound.     It 
is  said  that  the  Indian  of  our  western  prairies  can,  by  listening 
at  the  surface  of  the  ground,  hear  the  advance  of  a  troop  of 
cavalry  while  they  are  still  out  of  sight,  and  can  even  discrim- 
inate between  their  tread  and  that  of  a  herd  of  buffaloes.     Solid 
substances  also  convey  sounds  with  greater  power  than  air. 

Some  have  thought,  by  the  early  use  of  spectacles,  to  be  able  to  preserve 
their  power  of  vision,  and  have  recommended  and  employed  '  conservative 
glasses.'  If  I  am  not  mistaken,  self-interest  had  something  to  do  with 
this  recommendation.  So  long  as  the  eye  does  not  err,  and  remains  free 
from  fatigue  in  the  work  required  of  it,  its  own  power  is  sufficient,  and  it 
is  inexpedient  to  seek  assistance  in  the  use  of  convex  glasses."  —  Dr. 
B.  Joy  Jeffries.  

86.  Hearing  ?    What  is  sound  ?    How  propagated  commonly  ? 

87.  Sound-wave  in  the  atmosphere  ?     It*  shape?    Kate  of  motion  ?    Sound  in  air,  water, 
and  solid  bodies  ? 

88.  Thfr«arth  as  a  conductor  of  sound  ?    What  has  the  western  Indian  been  taught? 
Solid  substances  as  conductors  ?    As  regards  sound,  in  what  respect  is  air  necessary  ? 
Sound  in  a  vacuum  ? 


306  THE  SPECIAL  SENSES 

If  the  ear  be  pressed  against  one  end  of  a  long  beam,  the 
scratching  of  a  pin  at  the  other  extremity  may  be  distinctly 
heard,  which  will  not  be  at  all  audible  when  the  ear  is  removed 
from  the  beam.  Although  air  is  not  the  best  medium  for  con- 
veying sound,  it  is  necessary  for  its  production.  Sound  can- 
not be  produced  in  a  vacuum,  as  is  shown  by  ringing  a  bell  in 
the  exhausted  receiver  of  an  air-pump,  for  it  is  then  entirely 
inaudible.  But  let  the  air  be  re-admitted  gradually,  then  the 
tones  become  more  and  more  distinct,  and  when  the  receiver  is 
again  full  of  air,  they  will  be  as  clear  as  usual. 

89.  All  sonorous  bodies  do  not  vibrate  with  the  same  degree 
of  rapidity,  and  upon  this  fact  depends  the  pitch  of  the  sounds 
that  they  respectively  produce.     The  more  frequent  the  num- 
ber of  vibrations  within  a  given  time,  the  higher  will  be  the 
pitch ;  and  the  fewer  their  number,  the  lower  or  graver  will  it 
be.     Now,  the  rate  of  the  successive  vibrations  of  different 
notes  has  been  measured,  and  it  has  thus  been  found  that  if 
they  are  less  than  sixteen  in  a  second,  no  sound  is  audible ; 
while,  if  they  exceed  60,000  per  second,  the  sound  is  very 
faint,  and  is  painful  to  the  ear.     The  extreme  limit  of  the 
capacity  of  the  human  ear  may  be  considered  as  included 
between  these  points,  but  the  sounds  which  we  ordinarily  hear 
are  embraced  between  100  and  3000  vibrations  per  second. 

90.  The  ear,  which  is  the  proper  organ  of  hearing,  is  the 
most  complicated  of  all  the  structures  that  are  employed  in 
the  reception  of  external  impressions.     The  parts  of  which  it 
is  composed  are  numerous,  and  some  of  them  are  extremely 
small  and  delicate.     Nearly  all  these  parts  are  located  in  an 
irregularly  shaped  cavity  hollowed  out  in  the  temporal,  or 
"temple"  bone  of  each  side  of  the  head.     That  part  of  the 
bone  in  which  the  auditory  cavity  is  placed  has  the  densest 
structure  of  all  bones  .of  the  body,  and  has,  therefore,  been 
called  the  "  petrous,"  or  rocky  part  of  the  temporal  bone.     In 
studying  the  ear,  it  is  necessary  to  consider  it.  as  divided  into 
three  portions,  which  are  called,  from  their  relative  positions, 

89.  Pitch?    To  what  due?    Capacity  of  ear ? 

90.  The  ear.    Its  divisions. 


THE  SPECIAL  SENSES 


307 


the  external  ear,  the  middle  ear,  and  the  internal  ear.  (In  the 
diagram,  Fig.  70,  A,  the  first  is  not  shaded,  the  second  is  lightly 
shaded,  and  the  last  has  a  dark  background.) 

91.  The  External  Ear.  —  The  external  portion  of  the  organ 
of  hearing,  designated  in  Fig.  70,  A,  includes,  first,  that  outer 
part  (a),  which  is  commonly  spoken  of  as  "the  ear,"  but  which 


Fie.  70.— THE  EAR  AND  ITS  DIFFERENT  PARTS 

A,  Diagram  of  the  Ear 

a,  6,  External  Ear  d ,  Middle  Ear 

c,  Membrana  tympani  «,  Internal  Ear 

B  to  B'",  Bones  of  the  Middle  Ear  (magnified) 
C,  The  Labyrinths  or  Internal  Ear  (highly  magnified) 

in  fact  is  only  the  portal  of  that  organ;  and,  secondly,  the 
auditory  canal  (b).  The  former  consists  of  a  flat,  flexible  piece 
of  cartilage,  projecting  slightly  from  the  side  of  the  head, 
attached  to  it  by  ligaments,  and  supplied  with  a  few  weak 
muscles.  Its  surface  is  uneven,  and  curiously  curved,  and  from 
its  resemblance  to  a  shell  it  has  been  called  the  concha.  It 
probably  serves  to  collect  sounds,  and  to  give  them  an  inward 
direction,  although  its  removal  is  said  not  to  impair  the  aqute- 
ness  of  hearing  more  than  a  few  days. 

91.   Of  what  does  the  external  portion  of  the  organ  of  hearing  consist  ?     Describe  th« 
portal  of  that  organ  known  as  the  ear.     Its  use  ? 


308  THE  SPECIAL  SENSES 

92.  In  those  animals  whose  hearing  is  more  delicate  than 
that  of  man,  the  corresponding  organ  is  of  greater  importance, 
it  being  larger,  and  supplied  with  muscles  of  greater  power, 
so  that  it  serves  as  a  natural  kind  of  ear-trumpet,  which  is 
easily  movable  in  the  direction  of  any  sound  that  attracts  the 
attention  of  the  animal.    Bold,  preying  animals  generally  have 
the  concavity  of  this  organ  directed  forward,  while  in  timorous 
animals,  like  the  rabbit,  it  is  directed  backward.     Fishes  have 
no  outer  ear,  but  sounds  are  transmitted  directly  through  the 
solid  bones  of  the  head,  to  the  internal  organ  of  hearing. 

93.  The  auditory  canal  (Fig.  70,  A,  6),  which  is  continuous 
with  the  outer  opening  of  the  ear,  is  a  passage  an  inch  and 
a  quarter  in  length,  its  inner  extremity  being  bounded  by  a 
closely  fitting,  circular  membrane.     This  canal  is  of  oval  form, 
is  directed  forward  and  inward,  and  is  slightly  curved,  so  that 
the  inner  end  is  ordinarily  concealed  from  view.     The  pouch 
of  the  skin  which  lines  this   passage   is   smooth  and   thin, 
especially  at  the  lower  end,  where  it  covers   the  membrane 
just  mentioned. 

94.  As  in  the  case  of  the  nostrils,  a  number  of  small,  stiff 
hairs  garnish  the  margin  of  the  auditory  canal,  and  guard  it, 
to  some  extent,  against  the  entrance  of  insects  and  other  for- 
eign objects.    The  skin,  too,  covering  its  outer  half,  is  furnished 
with  a  belt  of  little  glands  which  secrete  a  yellow,  bitter  sub- 
stance, called  "  ear-wax,"  which  is  especially  obnoxious  to  small 
insects.     As  the  outer  layer  of  this  wax-like  material  loses  its 
useful  properties  it  becomes  dry,  and  falls  out  of  the  ear  in  the 
form  of  minute,  thin  scales,  a  fresh  supply  being  furnished 
from  the  little  glands  beneath.     In  its  form,  the  auditory  canal 
resembles  the  tube  of  an  ear-trumpet,  and  serves  to  convey  the 
waves  of  sound  to  the  middle  portion  of  the  ear. 

95.  The  Middle  Ear,  or  Tympanum.  —  The  middle  ear  is  a 
small  cavity,  or  chamber,  of  irregular  shape,  about  one-fourth 
of  an  inch  across  from  side  to  side,  and  half  an  inch  long  (see 

92.  The  ear  in  the  animals  of  delicate  hearing  ?    Rabbit?    Fishes? 

98.  What  is  the  auditory  canal  ?    Describe  it. 

'     94.  How  is  it  guarded  and  protected  ?    "  Ear-wax  "  ? 

95.  What  is  the  middle  ear  *    Why  called  tympanum  f 


THE  SPECIAL  SENSES  309 

Fig.  70,  A,  d).  From  the  peculiar  arrangement  of  its  various 
parts  it  has  very  properly  been  called  the  tympanum,  or  the 
"drum  of  the  ear."  The  middle  ear,  like  the  external  canal, 
contains  air. 

96.  The  circular  membrane,  already  mentioned  as  closing  the 
auditory  canal,  is  the  partition  which  separates  the  middle 
from  the  external  ear,  and  is  called  the  membrana  tympani  (c), 
and  may  be  considered  as  the  outer  head  of  the  drum  of  the 
.ear.  It  is  sometimes  itself  spoken  of  as  the  "drum,"  but  this 


FIG.  71.— SHOWING  THE  INTERNAL  MECHANISM  or  THE  EAR  (GREATLY  ENLARGED") 

is  incorrect,  since  a  drum  is  not  a  membrane,  but  is  the  hollow 
space  across  which  the  membrane  is  stretched.  This  mem- 
branous drum-head  is  very  tense  and  elastic,  and  so  thin  as  to 
be  almost  transparent;  its  margin  is  fastened  into  a  circular 
groove  in  the  adjacent  bone.  Each  wave  of  sound  that  touches 
this  delicate  membrane  causes  it  to  vibrate,  and  it,  in  turn, 
excites  movements  in  the  parts  beyond. 

97.  Within  the  tympanum  is  arranged  a  chain  of  remark- 
able "little  bones,"  or  ossicles.     They  are   chiefly  three  in 

96.  What  is  the  membrana  tympani  ?    Describe  it. 

71.  What  are  the  ossicles  ?    Their  number  and  names  ?    Their  arrangement  ? 


310  THE  SPECIAL  SENSES 

number,  and  from  their  peculiar  shapes  bear  the  following 
names :  malleus,  or  the  mallet ;  incus,  or  the  anvil ;  and  stapes, 
or  the  stirrup.  A  fourth,  the  smallest  bone  in  the  body,  in 
early  life  intervenes  between  the  incus  and  the  stapes,  but  at 
a  later  period  it  becomes  a  part  of  the  incus.  It  is  called  the 
orbicular  bone.  Small  as  are  these  ossicles  —  and  they,  together, 
weigh  only  a  few  grains  —  they  have  their  little  muscles,  carti- 
lages, and  blood-vessels,  as  perfectly  arranged  as  the  larger 
bones  of  the  body.  One  end  of  the  chain  of  ossicles,  the  mal- 
let, is  attached  to  the  membrane  of  the  tympanum,  or  outer 
drum-head,  while  the  other  end,  the  stirrup,  is  firmly  joined 
by  its  foot-piece  to  a  membrane  in  the  opposite  side  of  the 
cavity.  The  chain,  accordingly,  hangs  suspended  across  the 
drum  between  the  two  membranes;  and  when  the  outer  one 
vibrates  under  the  influence  of  the  sound-wave,  the  chain 
swings  inward  and  transmits  the  vibration  to  the  entrance  of 
the  inner  ear. 

98.  The  musical  instrument,  the  drum,  is  not  complete  if 
the  air  within  be  perfectly  confined;  we  therefore  find  in  all 
instruments  of  this  kind  a  small  opening  in  the  side,  through 
which  air  may  pass  freely.     By  this  means  the  pressure  of  the 
air  upon  the  vellum  which  forms  the  head  of  the  duurn  is  made 
equal  upon  all  sides,  and  the  resonance  of  the  drum  remains 
unaffected  by  the  varying  density  of  the  atmosphere.     It  will, 
therefore,  emit  its  proper  sound,  whether  it  be  struck  in  the 
rarefied  air  of  the  mountain-top,  or  in  the  condensed  air  of  a 
mine.     The  tympanum,  or  drum  of  the  ear,  in  like  manner  has 
an  opening,  by  means  of  which  it  communicates  freely  with 
the  external  air.     This  opening  is  a  narrow  canal,  about  an 
inch  and  a  half  long,  called  the  Eustachian  tube,  after  the  name 
of  its  discoverer,  Eustachius. 

99.  The  course   of  this   passage  is   indicated  in  Fig.  71, 
directed  downward  and   inward:    its  other  extremity  opens 
into  the  upper  part  of  the  throat.     The  passage  itself  is  ordi- 
narily closed,  but  whenever  the  act  of  swallowing  or  gaping 

98.  The  Eustachian  tube  ?    Describe  it,  and  state  its  use. 

99.  What  can  you  state  of  the  action  of  the  Eustachian  tube  ? 


THE  SPECIAL  SENSES  311 

takes  place,  the  orifice  in  the  throat  is  stretched  open,  and  the 
air  of  the  cavity  of  the  tympanum  may  then  be  renewed.  Air 
may  at  will  be  made  to  enter  through  this  tube,  by  closing  the 
mouth  and  nose,  and  then  trying  to  force  air  through  the  latter. 


FIG.  72.  —  SECTION  OF  THE  RIGHT  EAR 

A,  The  Concha  E,  Incus,  or  Anvil 

B,  Auditory  Canal  M,  Malleus,  or  Mallet 

C,  Membrane  of  the  Drum  I,    Eustachian  Tube 

(the  lower  half)  G,  Semicircular  Canals 

D,  A  Small  Muscle  H,  Cochlea,  or  Snail's  Shell 

When  this  is  done,  a  distinct  crackle  or  clicking  sound  is  per- 
ceived, due  to  the  movement  of  the  membranes,  and  of  the 
little  bones  of  the  ear. 

100.  The  Eustachian  tube  serves,  also,  as  an  escape-pipe  for 
the  fluids  which  form  within  the  middle  ear ;  and  hence,  when 
its  lining  membrane  becomes  thickened,  in  consequence  of  a 
cold  or  sore  throat,  and  the  passage  is  thus  more  or  less  choked 
up,  the  fluids  are  unable  to  escape  as  usual,  and  therefore 
accumulate  within  the  ear.  When  this  takes  place,  the  vibra- 
tions of  the  membrane  are  interfered  with ;  the  sounds  heard 

100.  What  other  purpose  does  the  Eustachian  tube  serve  ?  How  is  this  shown  ? 
"  Throat-deafness  "  ?  Primary  use  of  the  Eustachian  tube  f 


312  THE  SPECIAL  SENSES 

appear  muffled  and  indistinct;  and  a  temporary  difficulty  of 
hearing,  which  is  known  as  "  throat-deafness/'  is  the  result. 
This  result  resembles  the  effect  produced  by  interrupting  the 
vibrations  of  a  sonorous  body,  such  as  all  are  familiar  with ; 
if  the  finger  be  placed  upon  a  piano-string  or  bell  when  it  is 
struck,  the  proper  sound  is  no  longer  fully  and  clearly  emitted. 
But  the  primary  use  of  this  tube  is  to  afford  a  free  communi- 
cation between  the  middle  ear  and  the  external  atmosphere, 
and  thus  secure  an  equal  pressure  upon  both  sides  of  the  mem- 
brane of  the  drum  of  the  ear,  however  the  density  of  the  atmos- 
phere may  vary.  If,  from  undue  tension  of  the  membrane, 
pain  is  experienced  in  the  ears,  when  ascending  into  a  rare 
atmosphere,  as  in  a  balloon,  or  descending  into  a  dense  one, 
as  in  a  diving-bell,  it  may  be  relieved  by  repeating  the  act  of 
swallowing,  from  time  to  time,  in  order  that  the  inner  and 
outer  pressure  may  thus  be  promptly  equalized. 

101.  The  Internal  Ear,  or  Labyrinth.  —  The  most  essential 
part  of  the  organ  of  hearing  is  the  distribution  of  the  auditory 
nerve.     This  is  found  within  the  cavity  of  the  internal  ear, 
which,  from  its  exceedingly  winding  shape,  has  been  termed 
the  labyrinth  (see  Fig.  70,  c).      This  cavity  is  hollowed  out  in 
dense  bone,  and  consists  of  three  parts  —  the  vestibule  (a),  or 
ante-chamber,  which  is  connected  with  the  other  two ;  the  coch- 
lea (6),  or  snail's  shell ;  and  the  three  semicircular  canals  (c). 
The  manner  in  which  the  nerve  of  hearing  is  distributed  is 
remarkable,  and  is  peculiar  to  this  nerve.     In  the  vestibule 
and  the  canals  its  fibres  are  spread  out  over  the  inner  surface, 
not  of  the  bony  cavity,  but  of  a  membranous  bag,  which  con- 
forms to  and  partially  fills  that  cavity,  and  which  floats  in  it, 
being  both  filled  and  surrounded  with  a  clear,  limpid  fluid. 

102.  A  singular  addition  to  the  mechanism  of  hearing  is 
observed  within  this  membranous  bag  of  the  labyrinth.     This 
consists  of  two  small  oval  ear-stones,  and  a  quantity  of  fine 
powder  of  a  calcareous  nature,  which  is  called  "ear-sand." 
When  examined  under  the  microscope,  these  sandy  particles 

101.  The  essential  part  of  the  organ  of  hearing  ?    Its  location  ?    Formation  ? 

102.  Where  is  the  "  ear-sand  "  found  ?    Give  the  theory  as  to  its  use. 


THE  SPECIAL  SENSES  313 

are  seen  to  lie  scattered  upon  and  among  the  delicate  filaments 
of  the  auditory  nerve ;  and  it  is  probable  that,  as  the  tremulous 
sound-wave  traverses  the  fluid  of  the  vestibule,  the  sand  rises 
and  falls  upon  the  nerve-filaments,  and  thus  intensifies  the 
sonorous  impression. 

103.  In  the  cochlea,  or  snail's  shell,  which  contains  the 
fluid,  but  no  membrane,  the  nerve  branches  upon   a   spiral 
shelf,  which,  like  the  cochlea  itself,  takes  two   and.  a  half 
turns,  growing  continuously  smaller  as  it  winds  upward.     As 
many  as  three  thousand  nerve-fibres  of  different  lengths  have 
been  counted  therein;   these,  it  has  been  thought,  form  the 
grand,  yet  minutely  small  key-board,  upon  which  strike  all  the 
musical  tones  that  are  destined  to  be  conveyed  to  the  brain. 
The  vestibule,  it  is  also  supposed,  takes  notice  of  noise  as 
distinguished  from  musical  sounds;    while  the  office  of  the 
semicircular  canals  is,  in  part  at  least,  to  prevent  internal 
echoes,  or  reverberations. 

104.  The  vestibule  communicates  with  the  chain  of  bones  of 
the  middle  ear  by  means  of  a  small  opening,  called  the  "  oval 
window,"  or  fenestra  ovalis.     Across  this  window  is  stretched 
the  membrane,  which  has  already  been  alluded  to  as  being 
joined  to  the  stirrup-bone  of  the  middle  ear.     Through  this 
window,  then,  the  sound-wave,  which  traverses  the  external 
and  middle  ear,  arrives  at  last  at  the  labyrinth.     The  limpid 
fluid  which  the  latter  contains,  and  which  bathes  the  terminal 
iibres  of  the  nerve  of  hearing,  is  thus  agitated,  the  nerve-fibres 
are  excited,  and  a  sonorous  impression  is  conducted  to  the 
brain,  or,  as  we  say,  a  sound  is  heard. 

105.  Protection  of  the  Sense  of  Hearing.  —  From  what  has 
been  seen  of  the  complicated  parts  which  compose  the  organ  of 
hearing,  it  is  evident  that  while  many  of  them  possess  an 
exquisite  delicacy  of  structure,  Nature  has  well  and  amply 
provided  for  their  protection.-    We  have  observed  the  concealed 

108.  In  the  cochlea,  or  snail's  shell?  "  Key  -board  "  in  the  internal  ear  ?  The  vestibule  f 
Semicircular  canals  ? 

104.  With  what  does  the  vestibule  communicate  f  What  is  the  method  by  which  sound 
It  conducted  to  the  brain  ? 

1JC*  TL«  formation  of  the  organ  of  hearing  with  a  view  to  its  protection* 


314  THE  SPECIAL  SENSES 

situation  of  the  most  important  parts  of  the  mechanism  of  the 
ear  —  the  length  of  its  cavity,  its  partitions,  the  hardness  of 
its  walls,  and  its  communication  with  the  atmosphere ;  all 
these  provisions  rendering  unnecessary  any  supervision  or  care 
on  our  part  in  reference  to  the  interior  of  the  ear.  But  in 
respect  to  its  external  parts,  which  are  under  our  control  and 
within  the  reach  of  harm,  it  is  otherwise.  We  may  both 
observe  the  dangers  which  threaten  them,  and  learn  the  means 
necessary  to  protect  them. 

106.  Caution.  —  One  source  of  danger  to  the  hearing  consists 
in  lowering  the  temperature  of  the  ear,  especially  by  the  intro- 
duction of  cold  water  into  the  auditory  canal.     Every  one  is 
familiar  with  the  unpleasant  sensation  of  distension,  and  the 
confusion  of  sounds  which  accompany  the  filling  of  the  ear 
with  water  when  bathing :  the  weight  of  the  water  within  it 
really  distends  the  membrane,  and  the  cold  chills  the  adjacent 
sensitive  parts.     It  is  not  surprising,  therefore,  that  the  fre- 
quent introduction  of  cold  water,  and  its  continued  presence  in 
the  ear,  enfeebles  the  sense  of  hearing.     Care  should  be  taken 
to  remove  water  from  the  ear  after  bathing,  by  holding  the 
head  on  one  side,  and,  at  the  same  time,  slightly  expanding 
the  outer  orifice,  so  that  the  fluid  may  run  out.     For  a  like 
reason,  the  hair  about  the  ears  should  not  be  allowed  to  remain 
wet,  but  should  be  thoroughly  dried  as  soon  as  possible. 

107.  It  may  be  stated  as  a  general  rule,  to  which  there  are 
but  few  exceptions,  that  no  cold  liquid  should  ever  be  allowed 
to  enter  the  ear.     When  a  wash  or  injection  is  rendered  neces- 
sary, it  should  always  be  warmed  before  use.     The  introduction 
of  cold  air  is  likewise  hurtful,  especially  when  it  pours  through 
a  crevice  directly  into  the  ear,  as  it  may  often  do  through  the 
broken  or  partially  closed  window  of  a  car.     The  avoidance  of 
this  evil  gives  rise  to  another  almost  as  great,  namely,  the 
introduction  of  cotton  or  other  soft  substances  into  the  ear  to 
prevent  it  from  "catching  cold."      This  kind  of  protection 
tends  to  make  the  part  unnaturally  susceptible  to  changes  of 

106.  Danger  to  which  hearing  may  be  subjected  ?    Advice. 

107.  The  general  rule  as  to  the  use  of  water  for  the  ear  t 


THE  SPECIAL  SENSES  315 

temperature,  and  its  security  seems  to  demand  the  continued 
presence  of  the  "warm"  covering.  As  a  consequence  of  its 
presence,  sounds  are  not  naturally  conveyed,  and  the  sensitive- 
ness of  the  nerve  of  hearing  is  gradually  impaired. 

108.  The  chief  source  of  injury,  however,  to  the   ear  is 
from  the  introduction  of  solid  substances  into  the  auditory 
canal,  with  the  design  of  removing  insects  or  other  foreign 
objects  that  have  found  their  way  into  the  ear,  or  with  the 
design  of  scraping  out  the  ear-wax.     For  displacing  a  foreign 
object,  it  is  usually  sufficient  to  syringe  the  ear  gently  with 
warm  water,  the  head  being  so  held  that  the  fluid  easily 
escapes.     If  a  live  insect  has  gained  entrance  to  the  ear,  it 
may  first  be  suffocated  by  pouring  a  little  oil  upon  it,  and 
afterward  removed  by  syringing  the  ear  as  just  mentioned. 

109.  The  removal  of  ear-wax  is  generally  unnecessary ;  for, 
as  we  have  before  seen,  Nature  provides  that  the  excess  of  it 
shall  become  dry,  and  then  spontaneously  fall  out  in  the  form 
of  fine  scales.      The  danger  from  the  introduction  of  solid 
implements  into  the  outer  ear  is  chiefly  found  in  the  fact  that 
the  membrane  which  lies  at  the  bottom  of  it  is  very  fragile, 
and  that  any  injury  of  it  is  liable  to  impair  permanently  the 
hearing  of  the  injured  ear. 

110.  How  Alcohol  affects  the  Special  Senses.  —  The  narcotic 
or  benumbing  influence  of  alcohol  is  felt  by  all  forms  of  ner- 
vous tissue,  and  among  them  the  nerves  of  special  sense.    Vision 
is  more  susceptible  of  injury  by  this  poison  than  any  of  the 
other  senses,  and  it  may  be  either  slightly  impaired  or  wholly 
lost.     There  is,  in  such  cases,  a  progressive  loss  of  power  in 
the  optic  nerve  that  can  only  be  remedied  by  a  perpetual 
abandonment,  on  the  part  of  the  sufferer,  of  alcoholic  drink ; 
and  even  this  must  not  be  delayed  too  long  after  dimness  of 
sight  has  commenced. 

111.  Alcohol    and    Color-Blindness.  —  Progressive    loss    of 
color-perception  has  been  noticed  by  physicians   in  persons 

108.  Chief  source  of  injury  to  the  ear  ?    Directions  for  removing  foreign  objects  from 
the  ear  ?    Of  a  live  insect  ?  109.  The  removal  of  ear-wax  ? 

110.  Do  those  who  drink  alcohol  have  good  vision  ? 

111.  What  about  their  perception  of  color  ? 


316  THE  SPECIAL  SENSES 

who  use  liquor  habitually,  though  not  to  the  extent  of  intoxi- 
cation. This  form  of  gradually  growing  "color-blindness" 
becomes  a  matter  of  highest  importance,  since  it  may  occur 
in  a  railroad  engineer,  or  pilot,  who  drinks,  or  in  the  case  of 
some  official  responsible  for  the  lives  and  limbs  of  travelers  by 
steam.  No  persons  who  indulge  in  alcoholic  beverages  can 
safely  be  allowed  to  occupy  trusts  of  this  nature. 

112.  Effect  of  Alcohol  on  Other  Senses.  —  Hearing  and  taste 
are   dulled  by   alcohol.     Touch  is    indirectly   robbed   of    its 
efficiency  in  a  certain  proportion  of  cases,  where  a  tremor  of 
the  muscles  of  the  arm,  or  the  "  palsy  of  drunkards,"  occurs. 
Fine  penmanship  or  drawing,  and  the  use  of  keen-edged  tools, 
depend  upon  a  delicate  employment  of  touch ;  but  with  a  hand 
that  shakes  like  the  palsied  limb  of  an  aged  man,  this  becomes 
an  impossibility.     In  this  way  has  alcohol  deprived  many  a 
man  of  the  means  of  his  livelihood.     This  is  said  to  be  espe- 
cially true  of   those  who  belong  to  the  class  of  topers  who 
drink  little  and  often.     (Read  Note  IB,  page  238.) 

113.  False  Apparitions  due  to  Alcohol  —  Delirium  Tremens. — 
In  certain  diseases  the  eyes  appear  to  see  objects  that  do  not 
in  reality  exist  within  their  view.     High  fever  is  one  of  these 
diseases ;  delirium  tremens,  or  "  the  horrors,"  experienced  by 
some  hard  drinkers,  is  another.    The  latter  condition  is  marked 
by  a  variety  of  terrifying  and  loathsome  creatures;  if  there 
be   any  form  of  reptile  that   is  especially  repulsive  to  the 
delirious  person,  this  is  the  form  that  is  most  liable  to  haunt 
him.     These  false  images  may  be  dimly  seen  at  first,  but  as 
the  disease  progresses  they  generally  become  perfectly  distinct, 
and  real,  and  torturing;  many  a  victim  has  thrown  himself 
down  from  a  window,  regardless  of  its  height,  in  his  eager 
haste  to  escape  from  his  unreal  visions.    Alarming  sounds,  also, 
are  heard  in  some  cases  of  this  disorder. 

114.  The  Effect  of  Tobacco  upon  Vision.  — Oculists  are  nearly 
unanimous  in  the  opinion  that  impairment  of  sight  and  even 

'112.   Other  senses? 

113.  Are  unreal  objects  ever  seen  as  real  ?    How  ia  delirium  tremene  described  ? 

114.  Has  tobacco  any  influence  over  vision  f 


THE  SPECIAL  SENSES 


817 


its  utter  loss  may  result  from  tobacco  smoking,  the  optic  nerve 
being  gradually  impaired,  as  in  the  case  of  those  who  lose  their 
sight  by  alcohol,  as  described  in  the  foregoing  paragraph  of 
this  Chapter,  Section  109.  There  is  a  relief  for  this  approach- 
ing blindness  if  the  patient  will  consent  to  wholly  abstain  from 
tobacco ;  and  yet,  "  there  are  those  who  would  rather  smoke 
than  see,"  and  persist  in  the  injurious  habit  in  spite  of  every 
proper  medical  caution. 

115.  Certain  narcotic  substances  have  an  injurious  influence 
over  the.  sense  of  hearing ;  among  these  are  tobacco  and  coffee 
used  in  excess.  The  opium  habit  is  injurious  to  the  sense  of 
sight. 


Contents  of  the  Orbit 


THE  EYE 


Lids 


Muscles 


Lachrymal 
apparatus 


TOPICAL  OUTLINE 

Eyeball. 
Muscles. 
Blood-vessels. 
Nerves. 
Fatty  tissue. 

Lachrymal  or  tear  apparatus. 
Consist  of  folds  of  the  skin. 
Lined  with  a  mucous  membrane  (the  conjunc- 
tiva) ,  which  is  also  reflected  over  the  front  of 
the  ball. 

Closed  by  the  circular  orbicularis  muscle. 
.  Upper  lid  raised  by  a  special  muscle. 

(Superior  —  turns  the  eyeball  up- 
wards. 
Inferior — turns  the  eyeball  down- 

wards. 
External  —  turns     the     eyeball 

outwards. 

Internal  —  turns  the  eyeball  in- 
wards. 
Superior  —  turns      the      eyeball 

outwards  and  downwards. 
Inferior  —  turns  the  eyeball  out- 
wards and  upwards. 
(  Lachrymal  gland— in  the  upper  and  outer  part 

of  the  orbit. 
•{  Several  small  ducts. 

f  Constant. 
[  Secretion  .  .  j  Moistens  the  eyeball. 

[  Carried  off  by  the  nasal  duct. 


4Recti 


2  Oblique 


115.   Have  alcohol  and  tobacco  together  any  Influence  t    Other  Injuries  t 


318 


THE  SPECIAL  SENSES 


THE  EYE  . 

(continued) 


Coats 


Lens 


Chambers 


Optics 


Outer 


f  Sclerotic 


[  Cornea 


Choroid 


Middle 


Iris 


Retina . 


<  Tough,          fibrous, 

opaque. 
f  Transparent. 
I  Covers  the  front  cen- 
tral portion  of  the 
I     eye. 

Contains  black    pig- 
ment. 

Terminates  in  front 
by      the       ciliary 
processes. 
A  circular  perforated 

diaphragm. 
Aperture  called   the 

pupil. 

Pupil  contracted  by 
circular    muscular 
fibres  ;  and 
Dilated     by     radial 

fibres. 

j  Nervous  structures. 
1  Connective  tissue. 


C  Aqueous 


I  Vitreous 


Interior  . 

Situated  just  behind  the  iris. 
Double  convex.    Elastic. 
Back  surface  more  convex  than  the  front. 
Enclosed  in  a  capsule. 

Held  by  the  suspensory  ligament  at  its  circum- 
ference. 

Ligament   relaxed    by  the   contraction   of   the 
ciliary  muscle. 

j  Between  the  iris  and  the  cornea. 

'  Contains  a  watery  fluid. 

f  Includes  the  greater  portion  of 
the  ball. 

1  Contains  a  transparent  jelly-like 

[     substance. 
The  eye  a  camera  obscura  or  dark  chamber. 
Rays  of  light  converge  as  they  enter  the  cornea. 
Convergence  increased  by  the  lens. 
Image  (inverted)  falls  on  the  retina. 

<  Cornea  or  lens  too  convex. 

1  Eemedy  —  wear  concave  glasses. 

j  Cornea  or  lens  too  flat. 

(  Remedy  —  wear  convex  glasses. 

j  At  entrance  of  optic  nerve. 

1  Totally  insensitive  to  light. 

r  TV  of  an  inch  outside  the  blind 
spot. 

I  Marked  by  a  slight  depression. 

[  Most  sensitive  part  of  the  retina. 
Retina  retains  impressions  for  about  |  of  a  sec- 
ond after  its  exciting  cause  ceases. 


Short-sight . 
Long-sight  . 
Blind  spot  . 

Yellow  spot 


THE  SPECIAL  SENSES 


319 


Outer 


Middle 


Pinna 


Canal 


Bones 


Openings 


Internal 


Osseous 
labyrinth 

Membranous 
labyrinth 

Cartilaginous  framework. 

Fatty  tissue.  * 

Muscles. 

Skin. 

Collects  sound  waves  and  reflects 
^     them  into  the  auditory  canal. 
f  1J  inch  long. 

J  Closed  internally  by  the  drum. 
1  Glands— secrete  "wax." 
[  Hairs  —directed  outwards., 
An  irregular  cavity  in 'the  temporal  bone. 
( Malleus. 
I  Incus. 
[  Stapes. 
f  Fenestra  ova  lis  —  closed  by  the 

stapes. 

1  Fenestra  rotunda — closed  by  a 
I     membrane. 

Vestibule  -(  Central  Portion. 
'  Fenestra  ovalis. 
f  Three  in  number. 
\  Open  into  the  vesti- 
[     bule. 

(A  spiral  tube. 
2j    turns    round    the 
modiohu. 
Fenestra  rotunda. 
Within  the  osseous. 
Similar  in  shape. 
Surrounded  by  perilymph. 
Contains  endolymph. 
Otoliths  and  hair-like  processes. 
Terminal  fibres  of  auditory  nerve. 


Canals 


Cochlea 


QUESTIONS    FOR  TOPICAL   REVIEW 

FASR 

1.  What  is  said  of  the  production  of  sensation? 264,  265 

2.  What  is  said  of  the  variety  of  sensation? 265 

3.  What  is  said  of  the  general  sensibility? 266 

4.  What  is  said  of  the  sensation  of  pain  ? 267 

5.  What  is  said  of  the  uses  of  pain? 267-269 

6.  Say  what  you  can  of  the  special  sensation 269-271 

7.  Say  what  you  can  of  the  organs  of  touch 271,  272 

8.  Say  what  you  can  of  the  sense  of  touch 272-273 

9.  Say  what  you  can  of  the  delicacy  of  touch 274,  275 

10.  What  is  understood  of  the  sensations  of  temperature  and  weight  ?.  275,  276 

11.  What  is  understood  by  the  organ  of  taste  ? . 276,  277 

12.  What  is  understood  by  the  sense  of  taste  ? 277,  278 

13.  What  is  understood  by  the  relations  of  taste 279,  280 

14.  Explain  the  influence  of  education,  etc 280 

15.  Explain  the  sense  of  smell 280,  281 


320  THE  SPECIAL  SENSES 

PAGE 

16.  Explain  the  nerve  of  smell ' 281,  282 

17.  Explain  the  uses  of  the  sense  of  smell 282-284 

18.  Explain  the  sense  of  sight 285,  286 

19.  Give  the  statement  concerning  light  and  the  optic  nerve 286,  287 

20.  Give  the  statement  concerning  the  organ  of  sight 287,  288 

21.  Give  the  statement  concerning  the  orbits 288 

22.  Give  the  statement  concerning  the  eyelids 288,  289 

23.  Give  the  statement  concerning  the  lachrymal  fluid 290,  291 

24.  Give  the  statement  concerning  the  eyeball 291-293 

25.  Give  the  statement  concerning  the  iris 293-295 

26.  Give  the  statement  concerning  the  retina 295-298 

27.  Give  the  statement  concerning  the  crystalline  lens 298,  299 

28.  What  are  the  uses  of  the  lens? 299-301 

29.  What  about  long  and  short  sight  ? 301,  302 

30.  Explain  the  function  of  accommodation '. 302,  303 

31.  Explain  old  sight  or  presbyopia 304 

32.  Explain  hearing  and  sound 305-307 

33.  Explain  the  external  ear 307,  308 

34.  Explain  the  middle  ear 308-309 

35.  Explain  the  internal  ear 312,  313 

36.  What  is  said  of  the  protection  of  the  sense  of  hearing? 313,  314 

37.  What  caution  is  given  ? 314,  315 

38.  How  does  alcohol  affect  the  special  senses  ? ,. 315,  316 

39.  How  does  alcohol  affect  hearing,  taste,  and  touch  ? 316 

40.  Effect  of  tobacco  upon  vision  ? 316,  317 


CHAPTER   XI 

THE  VOICE 

Voice  and  Speech —  The  Larynx,  or  the  Organ  of  the  Voice —  The  Vocal 
Cords — The  Laryngoscope  —  The  Production  of  the  Voice — The  Use 
of  the  Tongue — The  Different  Varieties  of  Voice  —  The  Change  of 
Voice  —  Its  Compass —  Purity  of  Tone —  Ventriloquy 

1.  Voice  and  Speech.  — In  common  with,  the  majority  of  the 
nobler  animals,  man  possesses  the  power  of  uttering  sounds, 
which  are  employed  as  a  means  of  communication  and  expres- 
sion.   In  man  these  sounds  constitute  the  voice ;  in  the  animals 
they  are  designated  as  the  cry.     The  song  of  the  bird  is  a 
modification  of  its  cry,  which  is  rendered  possible  from  the  fact 
that  its  respiratory  function  is  remarkably  active.    The  sounds 
of  the   animals   are  generally   produced  by   means   of   their 
breathing   organs.     Among  the  insects,  they    are   sometimes 
produced  by  the  extremely  rapid  vibrations  of  the  wings  in 
the  act  of  flight,  as  in  the  case  of  the  mosquito;  or  by  the 
rubbing  together  of  hard  portions  of  the  external  covering  of 
the  body,  as  in  the  cricket.     Almost  all  kinds  of  marine  ani- 
mals are  voiceless.     The  tambour-fish  and  a  few  others  have, 
however,  the  power  of  making  a  sort  of  noise  in  the  water. 
(Head  Note  1.) 

2.  But  man  alone  possesses  the  faculty  of   speech,  or  the 
power  to  use  articulate  sounds  in  the  expression  of  ideas,  and 

1.  Voice  in  Man  and  Animals.  — "  The  human  voice,  taking  male 
and  female  together,  has  a,  range  of  nearly  four  octaves.  Man's  power 
of  speech,  or  the  utterance  of  articulate  sounds,  is  due  to  his  intel- 
lectual development  more  than  to  any  great  structural  difference  between 
him  and  the  Apes.  Song  is  produced  by  the  glottis,  speech  by  the 
mouth.  The  parrot  and  mocking-bird  use  the  tongue  in  imitating 
human  sounds."  —  Orion's  Zoology. 

1.  The  ottering  of  sounds  by  animals  ?    How  produced  ? 

2.  The  evidence  of  man's  superior  endowment  ?    What  is  stated  of  the  idiot  ?    Parrot  ? 
E»ven? 

321 


322  THE   VOICE 

in  the  communication  of  mind  with  mind.  Speech  is  thus  an 
evidence  of  the  superior  endowment  of  man,  and  involves  the 
culture  of  the  intellect.  An  idiot,  while  he  may  have  complete 
vocal  organs  and  full  power  of  uttering  sounds  or  cries,  is 
entirely  incapable  of  speech ;  and,  as  a  rule,  the  excellence  of 
the  language  of  any  people  will  be  found  to  be  proportional  to 
their  development  of  brain.  Man,  however,  is  not  the  only 
being  that  has  the  power  to  form  articulate  sounds,  for  the 
parrot  and  the  raven  may  also  be  taught  to  speak  by  rote ;  but 
man  alone  attaches  meaning  to  the  words  and  phrases  he 
employs. 

3.  Relation  to  Hearing.  —  Speech  is  intimately  related  to  the 
sense  of  hearing.  A  child  born  deaf  is,  of  necessity,  dumb 
also ;  not  because  the  organs  of  speech  are  imperfect,  for  he 
can  utter  cries  and  may  be  taught  to  speak,  and  even  to  con- 
verse in  a  rude  and  harsh  kind  of  language;  but  because  he 
can  form  no  accurate  notion  of  sound.  A  person,  whose  hear- 
ing is  not  delicate,  or  as  it  is  commonly  expressed,  who  "has 
no  ear  for  music,"  cannot  sing  correctly.  A  person  who  has 
impaired  hearing  commonly  talks  in  an  unnaturally  loud  and 
monotonous  voice.  These  examples  show  the  necessary  rela- 
tion of  intelligence  and  the  sense  of  hearing  with  that  form  of 
articulate  voice  which  is  termed  speech.  (Head  Note  2.) 

2.  Certain  Peculiarities  of  the  Voice.  —  "Voice  is  a  sound  produced 
in  the  throat  by  the  passage  of  the  air  through  the  glottis,  as  it  is  expelled 
from  the  lungs.  It  is  grave  and  strong  in  man,  soft  and  higher  in  women  ; 
it  varies  according  to  age.  It  is  alike  in  both  sexes  in  infancy,  but  is 
modified  in  youth  ;  then  the  voice  is  said  to  'change.'  In  the  young 
woman  it  descends  a  note  or  two  and  becomes  stronger.  In  the  young 
man  the  change  is  much  more  strongly  marked.  At  the  fourteenth  or 
fifteenth  year  the  voice  loses  its  regularity,  becomes  harsh  and  unequal ; 
the  high  notes  cannot  be  sounded,  while  the  grave  ones  make  their 
appearance.  A  year  is  generally  sufficient  for  this  change  to  be  complete, 
and  the  voice  of  the  child  gives  place  to  that  of  the  man.  Exercise  of  the 
voice  in  singing  should  be  very  moderate,  if  not  entirely  suspended,  while 
this  change  is  going  on.  Voice  is  divided  into  singing  and  speaking 
voice.  One  differs  from  the  other  almost  as  much  as  noises  do  from 
musical  sounds.  It  is  the  short  duration  of  speaking  sounds  which  dis- 


3.   Speech  and  hearing  ?    A  deaf  child  ?    Person  having  "  no  ear  for  music  "  ?    Impaired 
hearing  ?    What  do  the  examples  show  ? 


THE   VOICE  323 

4.  The  Organ  of  the  Voice.  —  The  essential  organ  of  the  voice 
is  the  Larynx.     This  has  been  previously  alluded  to  in  its 
relation  to  the  function  of  respiration ;  and,  in  the  chapter  on 
that  subject,  are  figured  the  front  view  of  that  organ  (Fig.  48), 
and  its  connection  with  the  trachea,  tongue,  and  other  neigh- 
boring parts  (Fig.  51).     It  is  situated  at  the  upper  part  of  the 
neck,  at  the  top  of  the  trachea,  or  tube  by  which  air  passes 
into  and  out  of  the  lungs.     The  framework  of  the  larynx  is 
composed  of  four  cartilages,  which  render  it  at  once  very 
strong  and  sufficiently  flexible  to  enable  it  t6  move  according 
to  the  requirements  of  the  voice. 

5.  The  names  of  the  cartilages  are  (1)  the  thyroid)  which  is 
a  broad,  thin  plate,  bent  in  the  middle  and  placed  in  the 
central  line  of  the  front  part  of  the  neck,  where  it  is  known 
as  the  pomum  Adami,  or  Adam's  apple  (Fig.  73,  B),  and  where 
it  may  be  felt  moving  up  and  down  with  each  act  of  swallow- 
ing ;  (2)  the  cricoitf,  which  is  shaped  like  a  seal  ring,  with  the 

tinguishes  them  from  those  of  singing.  This  is  proved  by  the  fact  that  if 
we  prolong  the  intonation  of  a  syllable,  or  utter  it  like  a  note,  the  musical 
sound  becomes  evident.  And  if  we  pronounce  all  the  syllables  of  a  phrase 
in  the  same  tone,  the  speaking  voice  closely  resembles  psalm-singing. 
Every  one  must  have  noticed  this  in  hearing  school-boys  recite  or  read  in 
a  monotone,  and  the  analogy  is  complete  when  the  last  two  or  three 
syllables  are  pronounced  in  a  different  tone.  Spoken  voice  is  moreover 
always  a  chant  more  or  less  marked,  according  to  the  individual  and  the 
sentiment  expressed.  The  accentuation  peculiar  to  certain  languages  also 
gives  the  speech  the  character  of  a  chant ;  to  a  French  ear  an  Italian 
preacher  seems  always  to  sing.  A  chant  also  is  caused  by  those  inflec- 
tions of  the  voice,  which  express  our  emotions  and  our  passions.  They 
extend  from  the  feeble  murmur,  which  the  ear  scarcely  perceives,  to  the 
piercing  cry  of  pain.  Affectionate,  sympathetic,  imperious,  or  hostile, 
they  sometimes  charm,  sometimes  irritate,  and  always  move  us.  It 
is  related  of  Gr£try,  that  he  amused  himself  by  noting  as  exactly  as 
possible  the  *  Bonjour,  monsieur  ! '  of  the  persons  who  visited  him  ;  and 
these  words  expressed  by  their  intonation,  in  fact,  the  most  opposite 
sentiments,  although  literally  the  same.  Baron,  the  comedian,  moved 
his  audience  to  tears  by  his  recitation  of  the  stanzas  of  the  song,  *  Si  le 
roi  m^avait  donne  Paris  sa  grancfville '  —  'If  the  king  had  given  me  Paris 
his  great  city.'  "  —  Le  Pileur  on  Wonders  of  the  Human  Body. 


4.  Organ  of  the  voice  ?    Where  situated  ?    Of  what  is  its  framework  composed  f 

5.  Names,  formation,  and  situation  of  the  cartilages  ? 


324 


THE   VOICE 


broad  part  placed  posteriorly  (Fig.  73,  E).  At  the  top  of  the 
cricoid  cartilage  are  situated  the  two  small  arytenoid  cartilages, 
the  right  one  of  which  is  shown  in  Fig.  73,  c.  These  latter 
little  organs  are  much  more  movable  than  the  other  two,  and 
are  very  important  in  the  production  of '  the  voice.  They  have 
a  true  ball-and-socket  joint,  and  several  small  muscles  which 
contract  and  relax  with  as  perfect  regularity  and  accuracy  as 
any  of  the  larger  muscles  of  the  body. 

6.  The  interior  of  the  larynx  is  lined  with  a  very  sensitive 
mucous  membrane,  which  is  much  more 

closely  adherent  to  the  parts  beneath 
'than  is  usually  the  case  with  membranes 
of  this  description.  The  epiglottis  (A), 
consisting  of  a  single  leaf-shaped  piece 
of  cartilage,  is  attached  to  the  front  part 
of  the  larynx.  It  is  elastic,  easily  moved, 
and  fits  accurately  over  the  entrance  to 
the  air-passages  below  it.  Its  office  is 
to  guard  these  delicate  passages  and  the 
lungs  against  the  intrusion  of  food  and 
other  foreign  articles,  when  the  act  of 
swallowing  takes  place.  It  also  assists 
in  modifying  the  voice. 

7.  The    Vocal    Cords.  —  Within   the 
larynx,  and  stretched  across  it  from  the 
thyroid  cartilage  in   front  to  the  ary- 
tenoid cartilages  behind,  are  placed  the 
two  sets  of  folds  called  the  vocal  cords. 

m,  1-1        FlG-   T3.  — SECTION   OP  THB 

The    Upper  Of   these,   One    On   each    Side,         LARYNX  AND  TRACHEA 

are  the  false  cords,  which  are  compara-  A,  The  Epiglottis 

,.,ni  T     •    a       .,  i  rm  B,  The  Thyroid  Cartilage 

tively  fixed  and  inflexible.     These  are  c,  Arytenoid  cartilage 
not  at  all  essential  to  the  formation  of  £'  Yent™^  of  ,the  Larrnx 

i  j      £       ^        t.  i_  •     •         j      E,  Cncoid  Cartilage 

vocal  sounds,  for  they  have  been  injured,   F,  Right  Vocal  Cord 
in  those   lower  animals  whose    larynx  H>TheTrachea 
resembles   that   of .  man,   without    materially   affecting  their 
characteristic  cries.     Below  these,  one  on  each  side,  are  the 

6.  Lining  of  the  interior  of  the  larynx  ?    The  epiglottis  ? 

3.  Where  are  the  vocal  cords  ?    The  false  cords  ?    The  true  cords  ? 


THE  VOICE  325 

two  vocal  cords  (Fig1.  73,  F),  which  pursue  a  similar  direction 
to  the  false  cords  —  namely,  from  before  backward.  They  are 
composed  of  a  highly  elastic,  though  strong  tissue,  and  are 
covered  with  a  thin,  tightly  fitting  layer  of  mucous  membrane. 
Their  edges  are  smooth  and  sharply  defined,  and  when  they 
meet,  as  they  do  in  the  formation  of  sounds,  they  exactly 
match  each  other. 

8.  Between  the  true  and  false  vocal  cords  is  a  depression  on 
each  side,  which  is  termed  the  ventricle  of  the  larynx  (Fig. 
73,  D).     The  integrity  of  these  two  cords,  and  their  free  vibra- 
tion, are  essential  to  the  formation  of  the  tones  and  the  modu- 
lation of  the  natural  voice.     This  is  shown  by  the  fact  that,  if 
one  or  both  of  these  cords  are  injured  or  become  diseased, 
voice  and  speech  are  weakened;  or  when  the  mucous  mem- 
brane covering  them  becomes  thickened,  in  consequence  of  a 
cold,  the  vocal   sounds   are  rendered  husky  and  indistinct. 
When  an  opening  is  made  in  the  throat  below  the  cords  —  as 
not  infrequently  occurs  in  consequence  of  an  attempt  to  com- 
mit suicide — voice  is  impossible  except  when  the  opening  is 
closed  by  external  pressure. 

9.  The  interval  or  space  between  the  true  cords  of  the  voice  is 
constantly  varying,  not  only  when  their  vocal  function  is  in  ex- 
ercise, but  also  during  the  act 
of  respiration.     Every  time 
the  lungs   are   inflated,  the 
space  increases  to  make  wide 
the  entrance  for  the  air,  and 
diminishes  slightly  during  ex- 
piration.   So  that  these  little 
cords  move  gen£ly  to  and  fro 
in  rhythm  with  the  expansion 
and  contraction  of  the  chest 
in  breathing.     These  move- 

FIO.  74.— A  VIEW  or  THE  VOCAL  CORDS  BY  ments  and   others    may   be 

MEANS  'or  THE  LARYNGOSCOPE  .  „  , , 

seen  to  take  place,  it  a  small 

8.  Where  is  the  ventricle  of  the  larynx?  The  essentials  to  the  formation  of  the  tones 
and  modulation  of  the  voice  ? 

^  Variation  in  the  interval  between  the  true  cords  of  the  voice  ?  Experiment  with  the 
mirror. 


326  THE   VOICE 

mirror  attached  to  a  long  handle  be  placed  back  into  the 
upper  part  of  the  throat;  the  handle  near  the  mirror  must 
be  bent  at  an  angle  of  45°,  so  that  we  may  look  "around 
the  corner,"  so  to  speak,  behind  the  tongue.  The  position 
which  the  mirror  must  assume  will  be  understood  by  refer- 
ence in  Fig.  51.  A  view  of  what  may  be  seen  under  favor- 
able circumstances,  during  tranquil  inspiration,  is  represented 
in  Fig.  74.  The  vocal  cords  are  there  shown  as  narrow, 
white  bands,  on  each  side  of  the  central  opening,  and  since 
the  image  is  inverted,  the  epiglottis  appears  uppermost.  The 
rings  partly  seen  through  the  opening  belong  to  the  trachea. 
This  little  mirror  is  the  essential  part  of  an  instrument,  which 
is  called  the  laryngoscope,  and  simple  as  it  may  seem,  it  is 
accounted  one  of  the  most  valuable  of  the  recently-invented 
appliances  of  the  medical  art. 

10.  The  Production  of  the  Voice.  —  During  ordinary  tranquil 
breathing,  no  sound  is  produced  in  the  larynx,  true  vocal  tones 
being  formed  only  during  forcible  expiration,  when,  by  an 


FIG.  75. —THE  DIFFERENT  POSITIONS  OF  THE  VOCAL  CORDS 

A,  The  position  during  inspiration.    B,  In  the  formation  of  low  notes.    C,  In  the  formation 

of  high  notes 

effort  of  the  will,  the  cords  are  brought  close  together,  and  are 
stretched  so  as  to  be  very  tense.  The  space  between  them  is 
then  reduced  to  a  narrow  slit,  at  times  not  more  than  -^  of 
an  inch  in  width ;  and  the  column  of  expired  air  being  forced 
through  it  causes  the  cords  to  vibrate  rapidly,  like  the  strings 
of  a  musical  instrument.  Thus  the  voice  is  produced  in  its 
many  varieties  of  tone  and  pitch;  its  intensity,  or  loudness, 
depending  chiefly  upon  the  power  exerted  in  expelling  the  air 

10.  The  formation  of  true  vocal  tones  f 


THE   VOICE  327 

from  the  lungs.  When  the  note  is  high,  the  space  is  dimin- 
ished both  in  length  and  width ;  but  when  it  is  low,  the  space 
is  wid^"  and  longer  (Fig.  75,  B,  c),  and  the  number  of  vibra- 
tions is  few  e  -  within  the  same  period  of  time. 

11.  The  personal  quality  of  the  voice,  or  that  which  enables 
us  to  recognize  a  person  by  his  speech,  is  mainly  due  to  the 
peculiar  shape  of  the  throat,  nose,  and  mouth,  and  the  reso- 
nance Of  the  air  contained  within  those  cavities.     The  walls  of 
the  chest  and  the  trachea  take  part  in  the  resonance  of  the 
voice,  the  air  within  them  vibrating  at  the  same  time  with 
the  parts  above -them.     This  may  be  tested  by  touching  the 
throat  or  breast-bone,  when  a  strong  vocal  effort  is  made.     The 
teeth  and  the  lips  also  are  important,  as   is   shown  by  the 
unnatural  tones  emitted  by  a  person  who  has  lost  the  former, 
or  by  one  who  is  affected  with  the  deformity  known  as  "  hare- 
lip."   The  tongue  is  useful,  but  not  indispensable  to  speech; 
the  case  of  a  woman  is  reported,  from  whom  nearly  the  whole 
tongue  had  been  torn  out,  but  who  could,  nevertheless,  speak 
distinctly  and  even  sing. 

12.  The  Varieties  of  voice  are  said  to  be  four  in  number; 
two,  the  bass  and  tenor,  belonging  to  the  male  sex ;  and  two, 
the  contralto  or  alto,  and  soprano,  peculiar  to  the  female.     The 
baritone  voice   is  the  name   given  to  a  variety  intervening 
between  the  bass  and  tenor.     In  man,  the  voice  is  strong  and 
heavy ;  in  woman,  soft  and  high.     In  infancy  and  early  youth, 
the   voice  is  the  same  in  both  sexes,  being  of   the   soprano 
variety :  that  of  boys  is  both  clear  and  loud,  and  being  sus- 
ceptible of  considerable  training,  is  highly  prized  in  the  choral 
services  of  the  church  and  cathedral.     At  about  fourteen  years 
of  age  the  voice  is  said  to  change  —  that  is,  it  becomes  hoarse 
and  unsteady  by  reason  of  the  rapid  growth  of  the  larynx.     In 
the  case  of  the  girl,  the  change  is  not  very  marked,  except 
that  the  voice  becomes  stronger  and  has  a  wider  compass  ;  but 
in  the  boy,  the  larynx  neaily  doubles  its  size  in  a  single  year, 
the  vocal  cords  grow  thicker,  longer,  and  coarser,  and  the  voice 

11.  To  what  is  the  personal  quality  of  the  voice  mainly  due  ?    What  aids  are  there? 

12.  Varieties  of  voice  ?    The  baritone  ?    The  voice  in  early  youth  ? 


328  THE  VOICE 

becomes  masculine  in  character.     During  the  progress  of  this 
change,  the  use  of  the  voice  in  singing  is  injudicious. 

13.  The  ordinary  range  of  each  of  the  four  varieties  of  the 
voice  is  about  two  octaves  ;  but  this  is  exceeded  in  the  case  of 
several  celebrated  singers.  Madame  Parepa  Rosa  had  a  com- 
pass of  three  full  octaves.  When  the  vocal  organs  have  been 
subjected  to  careful  training,  and  are  brought  under  complete 
control  of  the  will,  the  tension  of  the  cords  becomes  exact, 
and  their  vibrations  become  exceedingly  precise  and  true. 
Under  these  circumstances  the  voice  is  said  to  possess  "  purity  " 
of  tone,  and  can  be  heard  at  a  great  distance,  and  above  a 
multitude  of  other  sounds.  Some  years  ago  the  power  of  a 
pure  voice  to  make  itself  heard  was  exemplified  in  a  strik- 
ing manner  at  a  musical  festival  held  in  an  audience-room  of 
extraordinary  size ;  and  amid  an  orchestra  of  a  thousand  instru- 
ments and  a  chorus  of  twelve  thousand  voices,  the  artist  named 
above  also  sang ;  yet  such  was  the  purity  and  strength  of  her 
voice  that  its  notes  could  be  clearly  heard  rising  above  the 
vast  waves  of  sound  produced  by  the  full  accompaniment  of 
chorus  and  orchestra.  (Read  Note  3.) 

3.  The  Benefits  of  Vocal  Exercise.  —  "  Reading  aloud  and  recitation 
are  more  useful  and  invigorating  musical  exercises  than  is  generally  imag- 
ined, at  least  when  managed  with  due  regard  to  the  natural  powers  of  the 
individual,  so  as  to  avoid  effort  and  fatigue.  Both  require  the  varied 
activity  of  most  of  the  muscles  of  the  trunk  to  a  degree  of  which  few  are 
conscious,  till  their  attention  is  turned  to  it.  In  forming  and  undulating 
the  voice,  not  only  the  chest,  but  also  the  diaphragm  and  abdominal 
muscles  are  in  constant  action,  and  communicate  to  the  stomach  and 
bowels  a  healthy  and  agreeable  stimulus ;  and  consequently,  where  the 
voice  is  raised  and  elocution  rapid,  as  in  many  kinds  of  public  speaking, 
the  muscular  effort  comes  to  be  even  more  fatiguing  than  the  mental. 
When  care  is  taken,  however,  not  to  carry  reading  aloud  so  far  at  one 
time  as  to  excite  the  least  sensation  of  soreness  or  fatigue  in  the  chest, 
and  it  is  duly  repeated,  it  is  extremely  useful  in  developing  and  giving 
tone  to  the  organs  of  respiration,  and  to  the  general  system.  To  the 
invigorating  effects  of  this  kind  of  exercise,  the  celebrated  Cuvier  was  in 
the  habit  of  ascribing  his  own  exemption  from  consumption,  to  which,  at 
the  time  of  his  appointment  to  a  professorship,  it  was  believed  he  would 
otherwise  have  fallen  a  sacrifice.  The  exercise  of  lecturing  gradually 


18.  The  range  of  the  voice  ?    Kesult  of  careful  training  of  the  vocal  organs  ? 


THE   VOICE  329 

14.  In  the  production  of  the  articulate  sounds  of   speech, 
the  larynx  is  not  directly  concerned,  but  those  sounds  really 
depend  upon  alterations  in  the  shape  of  the  air-passages  above 
that  organ.    That  speech  is  not  necessarily  due  to  the  action  of 
the  larynx  is  proved  by  the  following  simple  experiment.     Let 
an  elastic  tube  be  passed  through  the  nostril  to  the.  back  of  the 
mouth.    Then,  while  the  breath  is  held,  cause  the  tongue,  teeth, 
and  lips  to  go  through  the  form  of  pronouncing  words,  and,  at 
the  same  time,  let  a  second  person  blow  through  the  tube  into 
the  mouth.      Speech,  pure  and  simple,  or,  in  other  words,  a 
whisper  is  produced.     Still  further  continue  the  experiment, 
while  permitting  vocal  sounds  to  be  made,  and  there  will  be 
produced  a  loud  and  whispering  speech  at  the  same  moment ; 
thus  showing  that  voice  and  speech  are  the  result  of  two  dis- 
tinct acts.     Sighing,  in  like  manner,  is  produced  in  the  mouth 
and  throat ;  if,  however,  a  vocal  sound  be  added,  the  sigh  is 
changed  into  a  groan. 

15.  Ventriloquism    is   a    peculiar  modification    of    natural 
speech,  which  consists  in  so  managing  the  voice  that  words 
and  sounds  appear  to  issue,  not  from   the   person,  but  from 
some  distant  place,  as  from  the  chimney,  the  cellar,  or  the 
interior  of  a  chest.'    The  original  meaning  of  the  word  ventril- 
oquism (that  is,  speaking  from  the  belly)  indicates  the  early 
belief    that  this   mode   of    speech   was   dependent  upon  the 
possession  and  use  of  some  special  organ  besides  the  larynx 
and   mouth;   but    at  the  present  time  it  is  known  that  it  is 
produced  by  these  organs  alone,  and  that  the  sources  of  decep- 
tion consist,  on  the  part  of  the  performer,  in  the  dexterous 
management  of  the  voice,  together  with  a  talent  for  mimicry ; 
and,  on  the  part  of  the  auditory,  in  the  liability  of  the  sense 
of  hearing  to  error  in  respect  to  the  direction  of  sounds.     The 

strengthened  his  lungs  and  improved  his  health  so  much  that  he  was  never 
afterward  threatened  with  any  serious  pulmonary  disease.  But,  of  course, 
this  happy  result  followed  because  the  exertion  of  lecturing  was  not  top 
great  for  the  then  existing  condition  of  his  lungs.11  — Combe's  Physiology. 


14.  The  production  of  the  articulate  sounds?    What  experiment  is  mentioned  ? 

15.  What  is  ventriloquism  ?    Indication  of  the  original  meaning  of  the  word  ?    How  are 
the  ventriloquous  sounds  produced  ? 


330  THE   VOICE 

ventriloquist  not  only  seems  to  "throw  his  voice,"  as  it  is  said, 
or  simulates  the  sound  as  it  usually  appears  at  a  distance  with 
but  little  motion  of  the  lips  and  face,  but  he  imitates  the  voices 
of  an  infant  and  of  a  feeble  old  man,  of  a  drunken  man  dis- 
puting with  an  exasperated  wife,  the  broken  language  of  a 
foreigner,  the  cry  of  an  animal  in  distress,  demonstrating  that 
the  performer  must  be  proficient  in  the  art  of  mimicry.  Ven- 
triloquism was  known  to  the  ancient  Romans  and  Greeks ;  and 
it  is  thought  that  the  mysterious  responses  that  were  said  to 
issue  from  the  sacred  trees  and  shrines  of  the  '.oracles  at 
Dodona  and  Delphi  were  really  uttered  by  priests  who  had 
the  power  of  producing  this  form  of  speech.  (Read  Notes  4  and  5.) 

4.  Improvement  of  Conversation  by  Vocal  Training.  —  "For  years 
I  had  fallen  into  a  low,  drawling,  lazy  tone  of  voice  in  my  ordinary  con- 
versation ;  my  utterance  came  forth  in  a  cloud,  and  had  its  dwelling  there. 
From  divers  experiments  and  observations  I  had  long  ago  assured  myself 
that  this  was  a  capital  defect ;  but  this  assurance  had  brought  with  it  no 
reform.     Now,  at  last,  I  attempted  it  in  good  earnest.     I  studied  to  bring 
myself  out  of  my  listlessness,  to  acquire  a  rapid,  distinct,  and  articulate 
enunciation.    No  man  can  miss  this  acquisition  unless  from  some  organic 
infirmity,  provided  only  that  he  pursue  it  steadily  and  earnestly.    I  em- 
ployed a  variety  of  exercises  for  the  voice,  as  recitation,  the  frequent 
repetition  of  the  same  passage,  slowly  at  first,  and  then  more  quickly,  up 
to  my  highest  pitch  of  rapidity,  the  pronunciation  of  foreign  languages,  — 
Greek  for  the  sake  of  fullness,  and  French  for  distinctness  and  despatch. 
As  a  result,  I  became  comparatively  a  clear  and  satisfactory  speaker ;  and 
as  my  talk  was  more  distinct  my  thoughts  were  all  the  more  pointed  and 
precise.     I  acquired  an  evenness  of  tone,  a  confidence,  a  complacency ; 
my  conversation,  as  the  French  say  of  their  language,  went  of  itself ;  I 
had  leisure  to  look  chiefly  to  my  direction,  to  march  on  to  my  object."  — 
Self- Formation,  by  Capel  Lofft. 

5.  Ventriloquism  and  Sound-Painting.  —  "Ventriloquism  bears  the 
same  relation  to   other  phenomena  of  sound  that  perspective  does  to 
optical  phenomena.    The  art  of  perspective  consists  in  portraying  upon  a 
flat  surface  the  appearance  of  objects  at  a  distance  from  it,  so  that  the 
same  effect  shall  be  produced  upon  the  eye  by  the  picture  as  would  be 
produced  by  the  objects  themselves.     In  order  to  do  this,  the  form,  tints, 
and  shades  are  reproduced,  not  as  they  really  are,  but  as  they  are  modified 
by  position  and  distance.     Or  it  may  be  said  to  consist  in  making  and 
arranging  a  group  of  objects  so  that  when  viewed  at  a  given  distance  they 
shall  produce  the  same  optical  effect  produced  by  another  set  of  objects 
arranged  in  different  positions  and  at  different  distances. 

"  Ventriloquism  consists  in  making  and  arranging  sounds  so  that  when 
heard  at  a  given  distance  they  shall  produce  the  same  effect  upon  the  ear 


THE   VOICE 


331 


that  ant  ther  set  of  sounds  produce  arranged  in  different  positions  and  at 
different  distances. 

"  Sounds  from  a  distance  are  of  course  weakened,  and  they  also  have 
another  quality  which  may  be  compared  to  the  indistinctness  of  outline 
in  objects  seen  at  a  distance.  In  proportion  as  the  fine  ear  of  the  ven- 
triloquist can  appreciate  these  modifications  will  be  his  success  in  imitating 
distant  sounds.  For  as  to  see  correctly  is  the  first  essential  to  success  in 
drawing,  so  is  hearing  correctly  the  first  essential  in  ventriloquism. 

"  There  are  many  sounds  which  cannot  be  imitated  by  voice  merely, 
such  as  the  singing  of  birds,  the  strident  noise  of  a  saw,  the  whistling  of 
a  plane,  etc.  Such  and  similar  unmusical  sounds  are  imitated  by  means 
of  the  teeth,  the  lips,  or  the  soft  parts  of  the  mouth.  Thus,  the  noise  of 
a  saw  is  like  that  produced  by  hawking,  only  much  prolonged,  and  modi- 
fied by  the  cheeks  ;  singing  of  birds  may  be  imitated  by  whistling  through 
the  teeth  ;  the  foaming  of  soda-water  by  breathing  with  open  lips  into  a 
tumbler,  etc.  To  persons  having  a  fine  ear  this  amusing  art  is  not  difficult, 
but  we  object  to  the  name  applied  to  it.  It  ought  to  be  called  sound- 
painting." 


LARYNX    . 


Thyroid 
Cricoid  . 


Arytenoid 


Glottis  . 


Epiglottis 


Vocal  cords 


TOPICAL  OUTLINE 

(  The  upper  cartilage, 
i  Wide  in  front ;  open  behind. 
J  A  complete  ring  of  cartilage. 
«  Wide  behind  ;  narrow  in  front. 

(Small  pyramidal. 
Surmount  the  upper  posterior  edge  of   the 
cricoid. 
Jointed  with  the  cricoid. 
{The  communication  between  the  pharynx  and 
the  larynx. 
Bounded  on  each  side  by  the  vocal  cords. 
(A  thin  movable  layer  of  cartilage. 
Closes  the   glottis  during  the  act  of   swal- 
lowing. 

Bands  of  elastic  fibres. 
Embedded  in  mucous  membrane. 
Relaxed  during  quiet  breathing. 
Stretched  during  speaking  and  singing. 
Attached  to  arytenoid  cartilages  behind,  and 
to  the  thyroid  in  front. 


QUESTIONS  FOR  TOPICAL  REVIEW 

PA0V 

1.  What  distinction  is  made  between  speech  and  voice  ? 321 

2.  What  is  said  of  each  ? 321,  322 

3.  What  does  speech  usually  indicate  ? 322 

4.  How  is  speech  related  to  hearing  ? 322 


332  THE  VOICE 


PAGB 

5.  Name  and  describe  the  organ  of  the  voice 323 

6.  What  other  organs  are  concerned  ? 323 

7.  What  offices  have  the  cartilages  ? 323,  324 

8.  Explain  and  locate  the  epiglottis 324 

9.  Say  what  you  can  of  the  vocal  cords 324-325 

10.  State  how  a*  cold  affects  the  voice 325 

11.  What  does  the  laryngoscope  reveal  to  us  ? 326 

12.  Upon  what  does  quality  of  voice  depend  ? 327 

13.  What  change  takes  place  when  the  voice  is  raised  ? 327,  328 

14.  How  do  the  chest  and  trachea  take  part  ? 327 

15.  How  the  teeth,  lips  and  tongue  ? 327 

16.  What  are  the  varieties  of  voice  ? 327 

17.  What  changes  take  place  with  age  ? 327,  328 

18.  Mention  the  ordinary  range  of  voice  and  instance  an  exception 328 

19.  What  further  is  said  of  speech  ? 329 

20.  What  is  ventriloquism  ? 329 

21.  How  produced  ? 329 

22.  What  mysteries  does  it  help  to  explain  ? 330 


CHAPTER  XII 

THE  USE  OF  THE  MICROSCOPE  IN  THE  STUDY 
OF  PHYSIOLOGY 

The  Law  of  Tissues  —  Necessity  of  the  Microscope  —  Different  Kinds  of 
Microscopes  —  Additional  Apparatus  —  Preliminary  Studies  —  The 
Study  of  Human  Tissues —  Tissues  of  the  Inferior  Animals  —  Incen- 
tives to  Study 

1.  The  Law  of  the  Tissues.  —  The  will  of  an  infinite  Creator 
is  obeyed  by  atoms  as  well  as  by  worlds.     He  has  seen  fit  to 
commit  all  the  functions  of  life  to  structures  or  tissues  so  small 
as  to  be  invisible  to  the  naked  eye.     A  muscle,  for  example,  as 
we  have  already  learned,  is  composed  of  innumerable  filaments, 
visible  only  by  the  aid  of  the  microscope;  and  the  power  of 
the  muscular  mass  is  but  the  sum  of  the  contractile  power  of 
the  filaments  which  enter  into  its  composition.     Again,  each 
cell  of  the  liver,  invisible  to  unassisted  sight,  is  a  secreting 
organ,  and  the  liver  performs  as  much  duty  as  the  sum  of  these 
minute  organs  renders  possible. 

2.  The  Necessity  of  the  Microscope.  —  If,  therefore,  we  would 
know  the  real  structure  of  the  human  body,  we  must  make  use, 
of  the  microscope.     Our  eyes  are  constructed  for  the  common 
offices  of  life,  to  provide  for  our  wants  and  guard  us  from  the 
ordinary  sources  of  danger ;  but  by  arming  them  with  lenses, 
the  real  structure  of  plants  and  animals  is  revealed  to  our  intel- 
ligence ;  and  enemies,  otherwise  invisible,  that  lie  in  wait  in 
the  air  we  breathe,  and  in  our  daily  food  and  drink,  to  destroy 
life,  are  guarded  against. 

1.  The  will  of  the  Creator,  by  what  obeyed  ?    The  power  of  a  muscle  ?    Amount  of  duty 
performed  by  the  liver  ? 

2.  Necessity  for  using  the  microscope  ?    The  advantages  gained  by  its  use  f 


334  THE  MICROSCOPE 

3.  Convex  Lenses,  or  magnifying  glasses,  are  disks  of  glass 
or  other  transparent  substances,  which  have  the  property  of 
picturing  itpon  the  retina  of  the  eye  an  image  of  an  object 
larger  than  the  image  produced  there  without  their  aid.  The 
glasses  used  in  microscopes  are  either  double  convex  lenses  (a) 
or  plano-convex  lenses  (5).  If  either  of  these  lenses  be  placed 
over  a  hole  in  the  shutter  of  a  darkened  room,  or  over  the  key- 
hole of  a  door,  and  a  piece  of  paper  be  held  at  a  proper  dis- 
tance, a  picture  of  all  objects  in  front  of  the  lens  will  be  thrown 
on  the  paper,  as  in  the  camera-obscura  or  the  magic-lantern. 
Now,  in  the  same  manner,  a  lens  throws  a  picture  of  objects 
to  which  it  is  directed  on  the  retina  of  the  eye,  and  when  that 

a  b 


* 


FIG.  76 


picture  is  larger  than  the  image  made  in  the  eye  l?y  the  object 
without  the  aid  of  the  lens,  it  is  magnified,  or  the  lens  has 
served  as  a  microscope,  so  called  from  its  use  in  seeing  small 
objects,  from  mikros,  small,  and  sJcopeo,  to  see. 

4.  Different  Kinds  of  Microscopes.  —  Microscopes  are  either 
simple  or  compound.      The  glasses  of  magnifying  spectacles, 
like  those  commonly  used  by  aged  persons,  are  simple  micro- 
scopes.    Magnifying  glasses,  mounted  in  frames,  such  as  are 
for  sale  by  opticians  and  others  for  the  detection  of  counter- 
feit money,  are  simple  microscopes,  and  are  useful  in  studying 
the  coarser  structure  of  plants  and  animals. 

5.  The  most  powerful  simple  microscopes  are  made  by  melt- 
ing in  a  flame  a  thread  of  spun  glass,  so  as  to  form  a  minute 

8.  What  are  convex  lenses  ?     Kind  of  lenses  used  in  microscopes  ?     Experiment  ? 
Picture  thrown  upon  the  eyes  ?    Derivation  of  the  word  microscope  ? 

4.  Kinds  of  microscopes  ?    What  are  simple  microscopes  ? 

5.  Construction  of  the  most  powerful  simple  microscopes  ?    In  practice  ?    A  doublet  ? 
Triplet  ?    Why  are  compound  microscopes  superior  to  simple  ones  ? 


THE  MICROSCOPE  335 

globule  or  bead,  which,  when  set  in  a  piece  of  metal  and  used 
to  examine  objects  on  a  plate  of  glass  held  up  to  the  light, 
gives  a  high  magnifying  power.  In  practice,  however,  it  is 
found  better  to  use  several  magnifying  glasses  of  moderate 
power  than  a  simple  lens  alone  of  high  power.  A  combination 
of  two  lenses  is  called  a  doublet — of  three,  a  triplet.  All  sim- 
ple microscopes  throw  an  enlarged  image  of  the  object  upon 
the  retina.  Compound  microscopes  are  so  constructed  that  the 
enlarged  image  of  an  object  is  again  magnified  by  a  second 
lens,  and  hence  their  magnifying  power  is  vastly  superior  to 
that  of  simple  microscopes. 

6.  The  accompanying  diagrams  will  explain  the  action  of 
the  compound  microscope  compared  with  that  of  the  simple 
microscope.  In  Fig.  77,  which  represents  the  working  of  the 
simple  microscope,  the  rays  from  the  object  (a  b),  passing 
through  the  lens  (L),  form  an  image  (a  fe')  in  the  retina  of  the 
eye  (E),  and  as  all  images  are  inverted  in  the  eye,  the  object  is 


FIG.  77.  —  SIMPLE  MICROSCOPE 

seen  as  all  other  objects  are,  and  appears  erect.  In  Fig.  78  is 
seen  the  action  of  the  compound  microscope.  An  inverted 
image  (a1  b1)  of  the  object  (a  b)  is  magnified  by  the  second  lens 
(L'),  and  an  erect  image  is  thrown  upon  the  retina,  which,  as 
all  other  objects  seen  erect  with  the  naked  eye  are  inverted, 
gives  to  the  image  a  contrary  direction,  or  inverts  it  to  the 
mind. 

7.  A  Compound  Microscope  consists  of  two  portions :  the 
optical  portion,  or  the  lenses,  and  the  mechanical  portion,  or 
the  instrument  which  bears  the  lenses.  The  glasses  of  a  com- 

6.  Explain,  by  means  of  the  diagram,  the  action  of  the  compound  microscope. 

7.  Portions,  in  a  compound  microscope  ?    The  glasses  2 


336 


THE  MICROSCOPE 


pound  microscope  are  two :  the  object-glass  and  the  lower  lens 
of  Fig.  78,  and  the  ocular  or  eye-piece  and  the  upper  piece  of 
Pig.  78.  Both  the  object-glass  and  the  eye-piece  may,  and 
usually  do,  consist  of  more  than  one  lens,  for,  as  has  been  pre- 
viously'mentioned,  better  results  are  obtained  by  a  combina- 
tion of  lenses  of  moderate  power  than  by 
single  lenses  of  high  power  and  great  curva1 
ture. 

8.  How  to  Choose  and  Use  a  Microscope.  — 

No  attractiveness  in  the  mechanical  part  of 
a  microscope  can  compensate  for  inferior 
lenses ;  and  the  very  first  consideration  in 
the  choice  of  an  instrument  should  be  the 
excellence  of  the  optical  part  of  the  instru- 
ment. In  the  use  of  the  instrument,  care 
should  be  exercised  to  keep  the  lenses  clean, 
free  from  dust,  not  to  press  the  object-glass 
upon  the  object  under  observation,  and  not 
to  wet  it  in  the  water  in  which  most  objects 
are  examined.  A  good  microscope  requires 
its  own  table ;  and  when  not  in  use,  should 
be  covered  by  a  bell  glass,  or  a  clean  linen 
cloth. 

9.  The  mechanical  portion  of  the  instru- 
ment varies  greatly  in  different  instruments. 
That  one  is  the  best  which  is  the  simplest, 
the  most  solid  and  most   easily  managed. 
Most  objects  in  human  anatomy  are  exam- 
ined in  water  or  in  other  liquids,  or  they  are 
themselves  liquids ;  hence  an  oblique  stage 
is  often  inconvenient. 


10.  Additional  Apparatus.  —  As  almost  all 
objects  in  human  anatomy  are  examined  by 
transmitted  light  thrown  up  from  the  mir- 


FIG.  78. —COMPOUND 
MICROSCOPE 


8.  How  to  choose  a  microscope  ?    How  to  use  it  ? 

9.  The   characteristics  of  the  best  instrument?     What  special  requisites  should  be 
Insisted  upon  ?    Why,  as  to  a  horizontal  stage  ? 

10.  Slides  ?    Covers,  square  and  circular  ?    How  kept  ? 


THE  MICROSCOPE  337 

ror  beneath  the  stage  through  the  object  to  the  eye,  they  must 
be  placed  upon  strips  of  clear  glass  about  three  inches  long, 
and  one  inch  wide,  commonly  called  "  slides."  These  should 
be  procured  with  the  microscope.  Again,  most  objects  seen 
with  high  powers  require  to  be  covered  with  a  thin  plate  of 
glass,  very  properly  called  a  "  cover,"  that  the  moisture  of  the 
specimen  may  not  tarnish  the  object-glass.  Square  or  circular 
covers  of  very  thin  glass  are  therefore  provided ;  and  a  good 
supply  of  these  should  be  always  on  hand.  These  glasses 
should  be  kept  in  a  covered  dish  filled  with  a  mixture  of  alco- 
hol and  water.  Simple  water  will  not  remove  the  fatty  matter 
which  exists  in  all  animal  tissues,  and,  therefore,  the  glasses 
cannot  be  thoroughly  cleaned  with  it  alone. 

11.  When  glasses   are   required  for  use,   they   should   be 
removed  from  the  liquid  and  wiped  clean  and  dry  with  a  soft 
linen  handkerchief.     Delicate  knives,  scissors,  needles  mounted 
in  handles,  forceps,  pipettes  or  little  tubes  for  taking  up  water, 
should  be  obtained;   these  are  essential  to  all  microscopical 
study.      The   table   should  be  supplied  with  glass-stoppered 
bottles  containing  the  various  liquids  ordinarily  used  in  the 
study  of  physiology.     Thus,  tincture  of  iodine  is  indispensable 
in  studying  vegetable  structure,  acetic  acid  in  the  study  of 
animal  tissues ;  and  other  articles  will  have  to  be  added  from 
time  to  time,  as  your  progress  in  study  demands  them. 

12.  Preliminary  Studies.  —  In  order  to  prepare  the  way  for 
the  study  of  any  department  of  science  with  the  aid  of  the 
microscope  —  for  the  microscope  is  but  an  eye,  and  can  be 
turned  in  almost  any  direction  for  purposes  of  investigation 
—  it  is  necessary  to  become  acquainted  with  the  many  objects 
which  are  liable  to  complicate  the  examination  of  particular 
structures.     Both  air  and  water  are  full  of   floating  bodies, 
and  the  most  common  of  these  should  first  occupy  the  atten- 
tion.    In  the  city,  particles  of  starch  are  always  floating  in  the 
air.     Take  a  very  minute  portion  of  wheat  flour,  place  it  in  the 
middle  of  a  clean  glass  "  slide,"  drop  upon  it  a  drop  of  pure 

11.  Cleaning  the  glasses  ?    Knives,  scissors,  etc.  ?    Various  liquids  f 

12.  Bodies,  in  ah-  and  water  ?    The  examination  of  starch  ? 


338  THE  MICROSCOPE 

water,  cover  it  with  a  plate  of  thin  glass,  and  examine  it  with 
a  power  of  from  one  hundred  to  six  hundred  diameters.  It 
will  be  found  td  be  composed  of  minute  grains  or  granules,  the 
largest  of  which  are  made  up  of  coats  or  layers,  like  an  onion, 
arranged  around  a  central  spot  called  the  hilum. 

13.  Make   another  preparation  in  the  .same  manner,  and, 
after  adding  the  water  and  before  covering  with  the  thin  glass 
cover,  add  a  small  drop  of  a  solution  of  iodine.     Now,  upon 
examining  the  specimen,  every  grain  will  be  seen  to  be  of  a 
beautiful  deep  blue  color.     After  thus  studying  wheat  starch, 
the  starch  of  Indian  corn,  of  arrow-root,  and  of  various  grains, 
should  be  examined  in  like  manner,  and  their  resemblances 
and  differences  noted.     The  granules  of  potato-starch  are  as 
distinctly  marked  as  any. 

14.  Fibres  of  cotton,  lint,  and  wool  are  liable  to  be  found  in 
every  specimen  prepared  for  microscopical  examination.     In 
order  to   study   these,   any   cotton,  woollen,  or   linen   fabric 
or   garment,  may  be   scraped,  and   the   scrapings   placed  on 
a  piece  of  glass  moistened  with  water,  covered  with  the  thin 
glass  plate  or  cover  as  before,  and  examined  with  the  same 
magnifying  power,  namely,  from   one   hundred  to   six  hun- 
dred   diameters.      Vegetable    hairs  'or    down    are    constantly 
floating  in  air  and  water.     These  are  of  very  various  forms, 
are  simple  or  grouped,  and  form  very  interesting  objects  of 
study.     They  are  readily  procured  from  the  epidermis  or  outer 
membrane  of  the  leaves  or  stems  of  plants,  by  cutting  with  a 
delicate  knife., 

15.  The  tissues  of  plants,  epidermis,  ducts,  and  woody  fibres 
are  constantly  found  in  microscopic  preparations.     They  may 
be  studied  in  delicate  sections  made  with  a  sharp  knife,  or  by 
tearing  vegetable  tissues  apart  with  needles.     The  down  of 
moths,  the  hairs  of  different  animals,  the  fibres  of  paper,  the 
most  common  animalcules  in  water,  the  dust  of  shelves,  and 
generally  the  structures  found  in  all  vegetable  and  animal  sub- 
is.  The  examination  with  solution  of  iodine  ?    Advice  respecting  other  articles? 

14.  Directions  for  examining  cotton  and  other  fibres  ?    Vegetable  hairs  ? 

15.  Directions  for  examining  various  tissues  ?    Down  of  moths  and  other  structures  ? 


THE  MICROSCOPE  339 

stances  by  which  we  are  surrounded,  should  be  studied  as  a 
preliminary  to  any  special  line  of  microscopical  investigation. 

16.  The  Study  of  Human  Tissues.  — When  this  has  been  done 
and  familiarity  with  the  use  of  the  instrument  has  been  ob- 
tained, proceed  to  the  study  of   the  human  body,  for  human 
physiology  is  our  subject.     If  the  end  of  the  finger  be  .pricked 
with  a  pin,  a  drop  of  blood  may  be  procured  for  examination. 
Place  this  on  one  of  the  glass  slides,  cover  it  with  a  thin  piece 
of  glass,  press  down  the  cover  so  as  to  make  a  thin  layer,  and 
then  examine  with  the  magnifying  power  just  mentioned.     Do 
not  add  water,  for  that  will  cause  the  blood  corpuscles  to  dis- 
appear.    If  the  drop  of  blood  is  placed  under  the  microscope 
at   once  after  being  drawn  from  the  finger,  most  interesting 
phenomena  will  be  observed.     The  red  corpuscles  will  be  seen 
to  arrange  themselves  in  rows,  like  piles  of   coin,  while   the 
blood  is  coagulating.     The  spherical,  white  corpuscles  will  be 
left  out  of  the  rows  of  red  discs,  and,  if  the  highest  power  be 
used,  will  be  seen  to  change  their  shape  constantly. 

17.  If  you  scrape  with  a  dull  knife  the  inside  of  the  cheek, 
the   flattened   scales   of    "pavement    epithelium,"   or   of  the 
insensible  covering  which,  analogous  to  the  scarf-skin  on  the 
outer  surface  of   the  body,  lines  the  cavities  of   its  interior, 
may  be  readily  studied.     They  have  the  appearance  of  trans- 
parent tiles,  each  enclosing  a  round  or  oval  body,  called  its 
nucleus.     Dandruff  and  the  scrapings  from  the  skin  of   the 
body  are  composed  of  scales  like  those  of  the  mouth,  but  they 
differ  somewhat  in  being  hardened. by  horny  matter,  and   in 
having  a  very  faint  central  body  or  nucleus. 

18.  The  Tissues  of  the  Inferior  Animals.  — The  warm-blooded 
animals  do  not  differ  in  the  tissues  or  microscopic  structures 
that  compose  them,  but  only  in  the  amount  and  arrangement 
of  these  tissues.     Milne-Edwards  says  these  tissues  "do  not 
differ  much  in  different  animals,  but  their  mode  of  association 


16.  Directions  for  examining  a  drop  of  blood  ? 

17.  Examination  of  the  scales  of  the  mouth  ?    Dandruff? 

18.  In  what,  as  respects  the  tissues,  do  the  warm-blooded  animals  differ  ?    Statement 
of  Milne-Edwards  ? 


340  THE  MICROSCOPE 

varies,  and  it  is  chiefly  by  reason  of  the  differences  in  the  com- 
bination of  these  associations  in  various  degrees,  that  each 
species  possesses  the  anatomical  properties  and  characters 
which  are  peculiar  to  it." 

19.  Hence  the  butcher's  stall  will  furnish  all  the  materials 
for  the  study  of  the  microscopic  tissues.     The  structure  of  the 
heart,  lungs,  liver,  brain,  and  muscle,  may  all  be  studied,  and 
well  studied,  by  using  minute  pieces  of  the  flesh  of  the  lower 
animals,  especially  of  the  quadrupeds.      Such  portions  of  these 
animals  as  are  not  exposed  for  sale  can  be  readily  obtained  by 
order  from  the  slaughter-house.     To  examine  with  the  powers 
of  which  we  have  been  speaking,  it  is  only  necessary  to  cut  off 
exceedingly  small  pieces,  tear  them  apart  with  needles,  or  make 
very  delicate  sections  with  a  sharp  knife. 

20.  Incentives   to    Study.  —  A  complete  knowledge   of   all 
minute  structures  is  not  to  be  expected  at  once,  for  you  are 
here  introduced  into  a  new  realm  of  Nature,  a  world  of  little 
things  as  vast,  as  wonderful,  and  as  carefully  constructed  as 
the  starry  firmament  —  that  other  realm  of  grand  objects  which 
the  astronomer  rightly  scans  with  the  telescope.     It  will  not 
appear  singular,  therefore,  if,  at  first,  you  feel  strange  and 
awkward  in  this  new  creation.      With  a  little  perseverance, 
however,  and  with  the  attention  directed  towards  simple  ob- 
jects at  the  outset,  it  will  not  be  long  before  an  increasing 
experience  will  engender  confidence. 

21.  If  to  all  this  there  be  added  an  enthusiastic  study  of 
the  standard  authorities  on  the  subject,  the  rate  of  progress 
will  be  much  more  rapid.     As  compared  with  similar  studies, 
few  possess  more  interest  than  microscopy,  and  to  the  one  who 
pursues  it  with  fondness,  it  constantly  affords  sources  of  pleas- 
ure and  agreeable  surprises ;  and  in  the  end  often  leads  to  new 
and  valuable  additions  to  the  sum  of  human  knowledge.     The 
depths  which  the  microscope  is  employed  to  fathom  are  no 
more  completely  known  than  are  the  heights  above  us  explored 
and  comprehended  by  the  astronomer. 

19.  How  to  procure  materials  for  the  study  of  the  tissues  of  man  ? 

20.  Incentives  to  study  ?        22.   How  may  the  rate  of  progress  be  increased  ? 


THE  MICROSCOPE  341 


QUESTIONS  FOR  TOPICAL  REVIEW 

'  PAGB 

1.  Say  what  you  can  of  the  law  of  the  tissues 333 

2.  What,  then,  is  the  necessity  of  the  microscope  ? 333 

3.  Define  and  state  use  of  convex  lenses 334 

4.  Name  some  of  the  kinds  of  microscopes 334,  335 

5.  Explain  action  of  compound  microscope 335 

6.  Of  what  parts  does  it  consist  ? 335,  336 

7.  What  parts  are  of  most  importance  ? 336 

8.  How  would  you  prepare  specimens  ? 336,  337 

*i.    What  further  directions  are  given  ? 337 

10.  What  is  said  of  preliminary  studies  ? 337-338 

11.  Give  statement  regarding  study  of  human  tissues 339 

12.  Tissues  of  inferior  animals 339,  340 


CHAPTER  XIII 

FIRST  HELP  IN  ACCIDENTS 

1.  Shock.  — The  term  shock  is  applied  to  a  condition  of  more 
or    less   severe  prostration,  the  result  of  some  severe  injury, 
accident,  or  fright.     It  may  or  may  not  be  accompanied  by 
loss  of  consciousness.     The  part  affected  is  the  nervous  sys- 
tem at  large,  and  hence  almost  all  the  organs  in  the  body  suffer 
more  or  less.      Persons  are  differently  affected  by  the  same 
injury ;  in  some,  a  comparatively  slight  accident  produces  a 
profound  degree  of  shock,  and  in  others,  a  severe  injury  only 
a  very  slight  degree.     The  lighter  forms  of  shock  usually  pass 
off  in  a  short  while,  but  in  the  severer  forms  a  person  may  die 
without  any  injury  being  present.     A  person  suffering  from 
shock  will  be  found  completely  prostrated,  unable  to  stand,  his 
body  limp,  face  pale  and  anxious,  covered  with  cold  perspira- 
tion, respiration  feeble  and  shallow,  pulse  either  very  feeble 
or  imperceptible,  and  he  may  be  conscious  or  unconscious. 

The  great  danger  to  this  person  lies  in  heart  failure,  and 
if  the  shock  is  profound,  death  may  ensue,  unless  help 
is  promptly  given.  Much  can  be  done  before  medical  aid 
arrives,  and  a  life  may  be  saved  by  prompt  action.  As  the 
heart  is  the  chief  organ  affected  through  the  nervous  system, 
everything  to  promote  its  action  should  be  done.  Place  the 
sufferer  flat  upon  his  back,'  with  the  head  low ;  loosen  all  tight 
clothing  about  the  neck  and  chest ;  give  whiskey  or  brandy  in 
hot  water  in  small  doses  at  intervals  of  fifteen  minutes  or 
half  an  hour ;  surround  the  body  with  hot-water  bottles,  and 
keep  the  patient  warm  and  quiet. 

2.  Fainting.  —  This  is  the  result  of  deficiency  of  blood  in 
the  brain.     Some  people,  especially  women,  faint  very  easily ; 

1.  Shock,  its  causes  and  symptoms  ?    Danger  ?    Treatment  ? 

2.  Fainting,  its  causes  and  treatment  ? 

342 


FIRST  HELP  IN  ACCIDENTS 


343 


the  sight  of  blood  or  surgical  instruments,  a  gruesome  story, 
the  recital  of  an  accident,  are  sufficient  causes.  As  a  rule,  the 
faint  is  of  short  duration,  and  all  that  is  necessary  is  to  place 
the  person  upon  the  back,  with  the  head  low ;  loosen  all  cloth- 
ing about  the  neck  and  chest ;  open  a  window  to  admit  fresh  air, 
and  sprinkle  the  face  with  cold  water.  If  the  faint  occurs  at 
church  or  at  some  public  gathering,  remove  the  person  promptly 
to  the  outer  air ;  for  foul  air  is  frequently  the  cause  of  the 
trouble.  If  after  the  above  means  have  been  employed  a 
person  does  not  regain  consciousness,  give  small  doses  (tea- 
spoonful)  of  whiskey  and  water,  equal  parts,  and  if  that  is  not 
sufficient,  elevate  the  legs  and  body,  so  as  to  promote  as  much 
as  possible  the  flow  of  blood  to  the  brain. 

3.  Vertigo.  —  This  is  "  a  rush  of  blood  to  the  brain."     The 
body  should  be  placed  in  a  sitting  posture,  with  the  head  erect. 
If  the  blood  escapes  into  the  brain  by  reason  of  the  rupture  of 
a  blood-vessel  within  it,  the  case  is  very  grave,  and  the  physi- 
cian should  be  summoned  at.  once.   Meanwhile,  let  the  position 
be  as  above  stated.     Apoplexy  is  known,  in  very  many  cases, 
by  the  helpless  condition  of  an  arm  or  leg,  or  both. 

4.  Hemorrhage,  or  Bleeding.  —  There  is  no  doubt  that  many 
a  life  has  been  lost,  from  severe  hemorrhage,  which  could  have 

been  saved,  had  intelligent  aid  been  at 
hand  to  stop  the  bleeding-point.  As  a 
rule,  the  bleeding  of  a  small  wound, 
although  profuse,  can  be  readily  con- 
trolled by  firm  pressure  over  it,  or  by 
tying  a  strip  of  bandage  round  it;  but 
in  the  severer  forms  of  hemorrhage, 
where  large  vessels  are  torn  or  cut, 
this  is  not  so  easily  accomplished. 
Learn  the  difference  between  the  two 
kinds  of  bleeding,  "arterial"  and  "ve- 
nous." Arterial  is  bright  red,  and  comes 
in  iets  (or  throbs  corresponding  to  the 

FIG.  7!*  J 

3.  Vertigo,  its  treatment?    Apoplexy,  how  known  ?  - 

4.  Hemorrhage,   or    Bleeding,   its    treatment?     Difference    between   "arterial"  and 
"  venous  "  bleeding  ?    Treatment  of  each  ?    Outfit  for  every  household  ? 


344 


FIRST  HELP  IN  ACCIDENTS 


pulse) ;  venous  is  dark-colored,  and  flows  continuously.  If  a 
larger  vessel  of  the  arm  or  leg  has  been  injured,  and  cannot  be 
controlled  by  direct  pressure,  tie  a 
cord  or  handkerchief  loosely  around 
the  limb  away  from  the  wound  on 
the  side  nearest  the  heart,  put  a 
stick  through  it  and  twist  until  the 
bleeding  stops.  In  addition  to  this, 
tie  a  pad  firmly  on  the  wound.  Loss 
of  blood  from  arteries  is  apt  to  be 
more  rapid  and  dangerous  than  that 
from  veins,  and  when  the  cut  vessel 
is  a  large  one,  the  skill  of  the  sur- 
geon will  ordinarily  be  required  in 
order  to  close  the  bleeding  artery 
permanently  and  securely. 

It  is  well,  in  every  household,  to 
have,  in  some  handy  and  well-known 
place,  some  strips  of  old  muslin  and 
some  lint,  or  oakum,  a  bandage  or 
two,  and  some  adhesive  plaster,  a  soft  sponge,  and  needles  and 
thread  in  a  basket  or  box  by  themselves.  In  this  way,  valu- 
able time  may  be  saved  in  the  staunching  of  blood,  flowing  in 
consequence  of  some  accidental  cut  or  other  injury. 

5.  Fractures  and  Dislocations. — A  broken  bone  in  surgical 
language  is  called  a  fracture  ;  a  bone  out  of  its  joint  is  called 
a  dislocation.  When,  in  addition  to  the  fracture,  there  is  pre- 
sent a  laceration  of  the  soft  parts  surrounding  it,  the  muscles 
and  the  skin,  so  that  the  broken  end  of  a  bone  protrudes 
through  the  latter,  we  speak  of  ,it  as  a  compound  fracture.  The 
symptoms  of  a  fracture  are :  pain  and  inability  to  move  the 
affected  limb ;  there  will  be  mobility  at  the  point  of  the  frac- 
ture, and  the  broken  ends  of  the  bone  may  be  felt  to  grate 
upon  each  other ;  if  the  leg  be  broken  at  any  point  the  patient 
will  be  unable  to  stand  upon  it. 

The  symptoms  of  a  dislocation  are:  altered  shape  of  the 


FIG.  80 


5.   Describe  a  fracture ;  a  dislocation  ;  a  compound  fracture ;  symptoms  of  each.     What 
can  be  done  for  each,  pending  the  arrival  of  surgical  aid  2 


FIRST  HELP  IN  ACCIDENTS  345 

limb ;  inability  to  move  it ;  great  pain  in  and  about  the  joint 
upon  the  slightest  attempt  at  motion. 

Much  can  be  done  for  the  comfort  of  a  patient,  pending  the 
arrival  of  surgical  aid.  First  of  all,  remember  that  a  person 
with  a  broken  bone  may,  without  suffering  harm,  wait  several 
hours  and  even  a  day  for  the  so-called  "  setting  "  of  the  bone. 
Kest  and  support  of  the  injured  member  are  the  two  things  to 
be  accomplished.  First  remove  all  clothing  from  the  arm  or 
leg,  best  by  slitting  the  garments  open,  and  not  by  pulling 
them  off ;  then  firmly  tie  a  strip  of  wood  on  either  side  of  the 
limb,  protecting  the  skin  by  padding  the  wood  well  with  any- 
thing soft,  cotton,  pieces  of  clothing,  etc.  A  good  support  is 
given  by  tying  a  pillow  firmly  around  the  arm  or  leg.  In 


FIG.  81 

moving  a  person  suffering  from  a  fractured  leg  or  arm,  some 
one  should  carry  the  broken  limb  carefully  and  evenly,  so  as 
to  avoid  all  jarring  and  all  motion  at  the  seat  of  the  fracture, 
which  would  be  extremely  painful.  Should  some  hours  have 
to  elapse  before  the  surgeon  arrives,  the  limb  should  be  in- 
spected from  time  to  time  to  see  that  the  cords  are  not  tied  too 
tightly,  for  considerable  swelling  follows  each  fracture. 

The  help  in  dislocations  lies  chiefly  in  the  proper  support  of 
the  limb  in  the  position  in  which  it  is  found.  In  moving 
a  person  suffering  from  a  dislocation,  let  one  person  support 
the  Iknb,  and  after  the  patient  is  at  rest,  place  it  in  the  posi- 
tion which  proves  the  most  comfortable  for  the  sufferer,  sup- 
porting it  on  either  side  with  pillows,  stones,  or  pieces  of  wood. 
Cold  water  compresses  to  the  joint,  if  there  is  much  pain,  will 
feel  most  grateful. 


346  FIRST  HELP  IN  ACCIDENTS 

6.  Sprains. — A  sprain  is  a   severe  straining  or  tearing  of 
the  ligaments  surrounding  a  joint.     In  the  milder  forms  these 
are  only  greatly  stretched,  but  in  the  more  severe  cases  they 
are  torn  entire  or  in  part,  in  some  cases  being  even  complicated 
by  a  tearing  off  or  breaking  of  the  ends  of  the  bones  forming 
the  joint.     Every  joint  may  suffer  from  a  sprain,  although  it 
is  most  frequently  met  with  in*  the  ankle. 

The  symptoms  of  a  sprain  are :  severe  pain  in  the  affected 
joint,  both  upon  motion  and  at  rest ;  swelling  sets  in  usually 
soon  after  the  receipt  of  the  injury,  and  blood  soon  makes  its 
appearance  under  the  skin,  coming  from  the  ruptured  blood- 
vessels. 

The  best  immediate  relief  that  can  be  given  is  to  place  the 
joint  in  hot  water,  as  hot  as  can  be  borne,  and  keep  it  there 
for  several  hours,  or  until  the  doctor  arrives,  adding  hot  water 
as  it  cools.  Should  medical  aid  not  be  obtainable,  then  take 
the  limb  out  of  the  hot  water  after  two  hours,  and  bandage  it 
firmly,  well  below  and  above  the  joint,  so  as  to  give  the  great- 
est support  and  prevent  all  motion. 

7.  Burns  and  Scalds.  —  The  secret  of  the  best  treatment  of 
these  injuries  is  to  exclude  the  air  from  the  wounded  surfaces. 
When  they  are  slight,  and  the  skin  is  not  destroyed,  but  merely 
blistered,  prevent  the  displacement  of  the  skin  as  much  as 
possible.     Let  the  blisters  be  punctured,  if  necessary,  to  let 
out  the  liquid,  and  then  keep  the  skin  in  place  by  cotton  cloth 
or  lint,  wet  with  a  solution  of  one  teaspoonful  of  carbolic  acid 
in  a  quart  of  water,  or  a  strong  solution  of  baking  soda.     The 
cloth  should  be  kept  wet  constantly,  but  do  not  irritate  the 
wound  by  taking  off  the  dressing  too  often. 

Extensive  burns  are  much  worse  than  deep  burns.  In  the 
former  case,  the  outlook  is  grave,  and  the  patient  will  probably 
require  the  best  aid,  both  medical  and  surgical,  of  some 
physician. 

Scars  after  Burns.  —  If  a  burn  be  on  the  face,  neck,  or  near 

6.  Sprains,  description,  symptoms,  immediate  relief?    How  treated  if  medical  aid  is  not 
obtainable  ? 

7.  Burns  and  scalds,  best  treatment  ?    What  are  the  worst  burns  ?    What  about  scars  ? 
Spontaneous  combustion  ?    What  should  be  done  when  a.  woman's  cloth.es  are  on  fire  ? 


FIRST  HELP  IN  ACCIDENTS  347 

a  joint,  it  is  not  well  to  hasten  the  healing  process,  on  account 
of  the  contraction  that  always  takes  place  as  the  scar  is  formed. 
"  Fire  is  a  source  of  danger,  and  is  very  destructive  to  life 
at  times.  Spontaneous  combustion  of  the  human  body  when 
saturated  with  alcohol  is  a  myth,  though  perhaps  the  alcohol- 
ized body  does  burn  more  readily  than  one  free  from  inflam- 
mable fluid.  When  a  lady  is  on  fire,  she  should  not  and 
ought  not  to  be  permitted  to  run ;  that  fans  the  flames 
amazingly.  She  must  be  laid  down  and  rolled  up  in  the 
nearest  woollen  article,  —  rug,  coat,  or  blanket.  Such  wrap- 
ping up  in  a  non-inflammable  article  is  a  most  effective  method 
of  extinguishing  the  flames.  Immersion  in  water  is,  unfortu- 
nately, rarely  practicable."  —  Fothergitt. 

8.  Illuminating  Gas  is  dangerous  in  two  ways.     If  it  escapes 
into  a  tightly  closed  room  in  sufficient  quantities,  it  causes  the 
death  of  the  inmates  by  suffocation,  unless  some  one  from 
without   discovers  the    perilous    situation.     If    not   too  late, 
remove  the  patient  into  fresh  air,  undo  the  clothing,  dash  cold 
water  on  the  face  and  neck,  and  employ  artificial  respiration, 
as  in  drowning  (see  p.  336).     Again :  If  it  escapes  freely  into 
an  apartment,  it  forms  an  explosive  compound  by  mixing  with 
the  air.     If  then  a  light  is  unguardedly  taken  into  the  place, 
an   explosion   that   may   be    destructive   fa  life   will  result. 
Always  thoroughly  air  any  room  that  has  the  odor  of  escaping 
gas  before  a  light  is  taken  in. 

9.  Kerosene  is  the  cause  of  even  more  "  accidents  "  than  gas. 
Too  much  care  cannot  be  taken  in  its  use.     Buy  only  that 
which  has  been  tested,  but  remember  that  not  all  that  are 
marked  as  "safe"  are  truly  so.     If  a  responsible  oil-man  certi- 
fies that  the  oil  will  not  "  flash  "  under  140  degrees,  it  may  be 
regarded  as  safe  if  properly  used.     Lamps  should  be  filled  only 
in  the  daytime.     Never  attempt  to  fill  a  lamp  that  is  lighted, 
and  never  put  kerosene  in  the  stove  for  the  purpose  of  kindling 
a  fire.     Very  small  lamps  are  dangerous,  as  also  is  a  lamp  that 
has  burned  a  long  time,  and  has  but  very  little  oil  in  it. 

8.  Illuminating  gas,  in  what  two  ways  dangerous  ? 

9.  Kerosene,  what  kind  to  use  ?    Cautions  to  be  observed  in  using  ? 


348  FIRST  HELP  IN  ACCIDENTS 

10.  Frost-bites. — Keep  away  from  the  fire  and  in  a  cool 
room.    Rub  the  nose,  or  other  part  that  has  been  "  bitten/'  with 
snow  or  ice-water  until  the  blood  is  warmed  again  and  circulat- 
ing in  the  part.     Chilblains  should  not  be  brought  to  the  fire : 
if  the  skin  is  unbroken,  it  should  be  hardened  by  brushing  it 
over  with  alcohol  having  tannin  in  it. 

11.  Sunstroke  is  seldom  produced  in  this  climate  in  persons 
who   have   not  labored  too  hard.     Fatigue  and  sun-heat  are 
commonly  the  joint  causes  of  sudden  prostration  in  summer ; 
although   "heat-stroke"   may   occur   in  an  artificially  heated 
atmosphere,  without  exposure  to  the  sun.     In  the  tropics,  the 
least  possible  exertion  is  put  forth  by  the  natives  during  the 
midday  hours.     On  very  hot  days,  therefore,  avoid  fatigue  and 
open-air  labor  as  much  as  possible.     Keep  the  head  cool.     If 
any  unusual,  dizzy  feeling  comes  on,  apply  cold  water  to  the 
head  and  neck.     If  a  person  falls  unconscious,  and  the  skin 
is  decidedly  hot  and  dry,  he  should  be  taken  to  a  cool  place. 
If  the   face   and  head  are  red  and  hot,  apply  ice-water  on 
cloths.      If  pale,  give  stimulants  gradually,  and  use  cold  water 
sparingly. 

12.  Fits  or  Convulsions. — These  may  be  trivial  or  grave. 
If  the  patient  is  a  young  woman,  the  attack  is  probably  hyster- 
ical, and,  as  a  rule,  not  dangerous,  and  a  sprinkle  of  cold  water 
will  bring  relief.     If  the  patient  struggles  with  regularity  of 
movement,  and  there  is  bloody  froth  on  the  lips,  it  is  a  case  of 
epilepsy,  and  requires  a  physician's  attendance.     Meanwhile, 
protect  the  head  from  injury  by  putting  a  pillow  or  some  soft 
article  beneath  it;  a  cork  introduced  between  the  teeth  will 
prevent  the  biting  of  the  tongue.     Prevent  the  person  from 
falling  or  injuring  himself,  but  do  not  attempt  to  forcibly  hold 
him  quiet. 

In  children  apply  cloths  dipped  in  water  to  the  head;  disturb 
the  child  as  little  as  possible;  do  not  use  a  warm  bath  until 
directed  by  the  doctor. 

10.  Frost-bites  and  chilblains, treatment  of  each  ? 

11.  Sunstroke,  causes  ?    Precautions  against ?    Treatment? 

12.  Fits  or  convulsions,  kinds  of  ?    Treatment  of  each  ? 


FIRST  HELP  IN  ACCIDENTS  349 

13.  Drowning. — Marshall  HaWs  "Ready  Method"  of  treat- 
ment in  asphyxia  from  drowning,  chloroform,  coal-gas,  etc. 

1st.  Treat  the  patient  instantly  on  the  spot,  in  the  open  air, 
freely  exposing  the  face,  neck,  and  chest  to  the  breeze,  except 
in  severe  weather. 

2d.  In  order  to  dear  the  throat,  place  the  patient  gently  on 
the  face,  with  one  wrist  under  the  forehead,  that  all  fluid,  and 
the  tongue  itself,  may  fall  forward,  and  leave  the  entrance  into 
the  windpipe  free. 

3d.  To  excite  respiration,  turn  the  patient  slightly  on  his 
side,  and  apply  some  irritating  or  stimulating  agent  to  the 
nostrils,  as  veratrine,  dilute  ammonia,  etc. 

4th.  Make  the  face  warm  by  brisk  friction ;  then  dash  cold 
water  upon  it. 

5th.  If  not  successful,  lose  110  time ;  but,  to  imitate  respircv- 
tion,  place  the  patient  on  his  face,  and  turn  the  body  gently, 
but  completely,  on  the  side,  and  a  little  beyond;  then  again  on 
the  face,  and  so  on,  alternately.  Repeat  these  movements 
deliberately  and  perseveringly,  fifteen  times  only  in  a  minute. 
(When  the  patient  lies  on  the  thorax,  this  cavity  is  compressed 
by  the  weight  of  the  body,  and  expiration  takes  place.  When 
he  is  turned  on  the  side,  this  pressure  is  removed,  and  inspira- 
tion occurs.) 

6th.  When  the  prone  position  is  resumed,  make  a  uniform 
and  efficient  pressure  along  the  spine,  removing  the  pressure 
immediately,  before  rotation  on  the  side.  (The  pressure  aug- 
ments the  expiration,  the  rotation  commences  inspiration.) 
Continue  these  measures. 

7th.  Rub  the  limbs  upward,  with  firm  pressure,  and  with 
energy.  (The  object  being  to  aid  the  return  of  venous  blood 
to  the  heart.) 

8th.  Substitute  for  the  patient's  wet  clothing,  if  possible, 
such  other  covering  as  can  be  instantly  procured,  each 
bystander  supplying  a  coat  or  cloak,  etc.  Meantime,  and 
from  time  to  time,  to  excite  inspiration,  let  the  surface  of  the 
body  be  slapped  briskly  with  the  hand. 

13.  Drowning.  What  is  Hall's  ready  method  of  treatment  in  asphyxia  from  drowning, 
chloroform,  coal-gas,  etc.  ? 


350  FIRST  HELP  IN  ACCIDENTS 

9th.  Bub  the  body  briskly  until  it  is  dry  and  warm,  then 
dash  cold  water  upon  it,  and  repeat  the  rubbing. 

Avoid  the  immediate  removal  of  the  patient,  as  it  involves  a 
dangerous  loss  of  time;  also,  the  use  of  bellows,  or  any  forcing 
instrument ;  also,  the  warm  bath,  and  all  rough  treatment. 

14.  Poisons  and  their  Antidotes.  —  Accidents  from  poisoning 
are  of  such  frequent  occurrence,  that  every  one  should  be  able 
to  administer  the  more  common  antidotes,  until  the  services  of 
a  physician  can  be  obtained.  As  many  poisons  bear  a  close 
resemblance  to  articles  in  common  use,  no  dangerous  substance 
should  be  brought  into  the  household  without  having  the  word 
poison  plainly  written  or  printed  on  the  label ;  and  any  pack- 
age, box,  or  vial,  without  a  label,  should  be  at  once  destroyed, 
if  the  contents  are  not  positively  known. 

When  a  healthy  person  is  taken  severely  and  suddenly  ill 
soon  after  some  substance  has  been  swallowed,  we  may  suspect 
that  he  has  been  poisoned.  In  all  cases  where  poison  has  been 
taken  into  the  stomach,  it  should  be  quickly  and  thoroughly 
expelled  by  some  active  emetic,  which  can  be  speedily  ob- 
tained. This  may  be  accomplished  by  drinking  a  tumblerful 
of  warm  water,  containing  either  a  tablespoonful  of  powdered 
mustard  or  of  common  salt,  or  two  teaspoonfuls  of  powdered 
alum  in  two  tablespoonfuls  of  syrup.  When  vomiting  has 
already  taken  place,  it  should  be  continued  by  copious  draughts 
of  warm  water  or  mucilaginous  drinks,  such  as  gum-water  or 
flaxseed  tea,  and  tickling  the  throat  with  the  finger  until  there 
is  reason  to  believe  that  all  the  poisonous  substance  has  been 
expelled  from  the  stomach. 

The  following  list  embraces  only  the  more  common  poisons, 
together  with  such  antidotes  as  are  usually  at  hand,  to  be  used 
until  the  physician  arrives :  — 

Acids.  —  Hydrochloric  acid  ;  muriatic  acid  (spirits  of  salt)  ; 
nitric  acid  (aqua  fortis) ;  sulphuric  acid  (oil  of  vitriol). 

ANTIDOTE.  —  An  antidote  should  be  given  at  once  to  neutral- 
ize the  acid.  Strong  soapsuds  is  an  efficient  remedy,  and  can 
always  be  obtained.  It  should  be  followed  by  copious  draughts 

14.   Give  class,  character,  and  antidote  of  each  ooiaon  mentioned  above. 


FIRST  HELP  IN  ACCIDENT!*  351 

of  warm  water  or  flaxseed  tea.  Chalk,  magnesia,  soda,  or  sale- 
ratus  (with  water),  or  lime-water  are  the  best  remedies.  When 
sulphuric  acid  has  been  taken,  water  should  be  given  sparingly, 
because,  when  water  unites  with  this  acid  intense  heat  is  pro- 
duced. 

Oxalic  acid. 

ANTIDOTE.  —  Oxalic  acid  resembles  Epsom  salts  in  appear- 
ance, and  may  easily  be  mistaken  for  it.  The  antidotes  are 
magnesia,  or  chalk  mixed  with  water. 

Prussic  acid  ;  oil  of  bitter  almonds  ;  laurel  water  ;  cyanide 
of  potassium  (used  in  electrotyping). 

ANTIDOTE.  —  Cold  douche  to  the  spine.  Chlorine  water,  or 
water  of  ammonia  largely  diluted,  should  be  given,  and  the 
vapor  arising  from  them  may  be  inhaled. 

Akalies  and  their  Salts.  —  AMMONIA  (hartshorn),  liquor  or 
tvater  of  ammonia.  POTASSA  :  —  caustic  potash,  strong  lye,  car- 
bonate of  potassa  (pearlash),  nitrate  of  potassa  (saltpetre). 

ANTIDOTE.  —  Give  the  vegetable  acids  diluted,  as  weak  vine- 
gar, acetic,  citric,  or  tartaric  acids  dissolved  in  water.  Castor 
oil,  linseed  oil,  and  sweet  oil  may  also  be  used ;  they  form 
soaps  when  mixed  with  the  free  alkalies,  which  they  thus 
render  harmless.  The  poisonous  effects  of  saltpetre  must  be 
counteracted  by  taking  mucilaginous  drinks  freely,  so  as  to 
produce  vomiting. 

Alcohol.  —  Brandy,  wine  ;  all  spirituous  liquors. 

ANTIDOTE.  —  Give  as  an  emetic  ground 'mustard  or  tartar 
emetic.  If  the  patient  cannot  swallow,  introduce  a  stomach 
pump ;  pour  cold  water  on  the  head. 

Gases.  —  Chlorine,  carbonic  acid  gas,  carbonic  oxide,  fumes  of 
I "r n  >ng  charcoal,  sulphuretted  hydrogen,  illuminating  or  coal  gas. 

ANTIDOTE.  —  For  poisoning  by  chlorine,  inhale,  cautiously, 
ammonia  (hartshorn).  For  the  other  gases,  cold  water  should 
be  poured  upon  the  head,  and  stimulants  cautiously  adminis- 
tered; artificial  respiration.  (See  Marshall  HaWs  Ready 
Method,  page  336.) 

Metals. — Antimony,  tartar  emetic,  wine  of  antimony,  etc. 

ANTIDOTE.  —  If  vomiting  has  not  occurred,  it  should  be  pro- 
duced by  tickling  the  throat  with  the  finger  or  a  feather,  and 


352  FIRST  HELP  IN  ACCIDENTS 

* 

the  abundant  use  of  warm  water.  Astringent  infusions,  such 
as  common  tea,  oak  bark,  and  a  solution  of  tannin,  act  as 
antidotes. 

Arsenic.  —  Wliite  arsenic.  Fowler's  solution,  fly  powder,  cobalt, 
Paris  green,  etc. 

ANTIDOTE.  —  Produce  vomiting  at  once  with  a  tablespoonful 
or  two  of  powdered  mustard  in  a  glass  of  warm  water,  or  with 
ipecac.  The  antidote  is  hydrated  peroxide  of  iron.  If  Fow- 
ler's solution  has  been  taken,  lime-water  must  be  given. 

Copper.  —  Acetate  of  copper  (verdigris),  sulphate  of  copper 
(blue  vitriol),  food  cooked  in  dirty  copper  vessels,  or  pickles 
made  green  by  copper. 

ANTIDOTE.  —  Milk  or  white  of  eggs,  with  mucilaginous 
drinks  (flaxseed  tea,  etc.),  should  be  freely  given. 

Iron.  —  Sulphate  of  iron  (copperas),  etc. 

ANTIDOTE.  —  Carbonate  of  soda  in  some  mucilaginous  drink, 
or  in  water,  is  an  excellent  antidote. 

Lead.  —  Acetate  of  lead  (sugar  of  lead),  carbonate  of  lead 
(white  lead),  water  kept  in  leaden  pipes  or  vessels,  food  cooked 
in  vessels  glazed  with  lead. 

ANTIDOTE.  —  Induce  vomiting  with  ground  mustard  or  com- 
mon salt  in  warm  water.  The  antidote  for  soluble  prepara- 
tions of  lead  is  Epsom  salts ;  for  the  insoluble  forms,  sulphuric 
acid  largely  diluted. 

Mercury.  —  Bi-chloride  of  mercury  (corrosive  sublimate), 
ammoniated  mercury  (white  precipitate),  red  oxide  of  mercury 
(red  precipitate),  red  sulphuret  f  mercury  (vermilion). 

ANTIDOTE. — The  white  of  eggs,  or  wheat  flour  beaten  up 
with  water  and  milk,  are  the  best  antidotes. 

Silver. — Nitrate  of  silver  (lunar  caustic). 

ANTIDOTE.  —  Give  a  teaspoonful  of  common  salt  in  a 
tumbler  of  water.  It  decomposes  the  salts  of  silver  and 
destroys  their  activity. 

Zinc.  —  Sulphate  of  zinc,  etc.  (white  vitriol). 

ANTIDOTE.  —  The  vomiting  may  be  relieved  by  copious 
draughts  of  warm  water.  The  antidote  is  carbonate  of  soda 
administered  in  water. 

Narcotic    Poisons.  —  Opium   (laudanum,   paregoric,   salts   of 


FIRST  HELP  IN  ACCIDENTS  353 

morphia,  Godfrey's  cordial,  Dalby's  carminative,  soothing 
syrup,  cholera  mixtures),  aconite,  belladonna,  hemlock,  stra- 
monium, digitalis,  tobacco,  hyosciamus,  nux  vomica,  strychnine. 

ANTIDOTE.  —  Evacuate  the  stomach  by  the  most  active  emet- 
ics, as  mustard,  alum,  or  sulphate  of  zinc.  The  patient  should 
be  kept  in  motion,  and  cold  water  dashed  on  the  head  and 
shoulders.  Strong  coffee  must  be  given.  The  physician  will 
use  the  stomach  pump  and  electricity.  In  poisoning  by  nux 
vomica  or  strychnine,  etc.,  chloroform  or  ether  should  be  in- 
haled to  quiet  the  spasms. 

Irritant  Vegetable  Poisons.  —  Croton  oil,  oil  of  savine,  poke, 
oil  of  tansy,  etc. 

ANTIDOTE.  —  If  vomiting  has  taken  place,  it  may  be  ren- 
dered easier  by  copious  draughts  of  warm  water.  But  if 
symptoms  of  insensibility  have  come  on  without  vomiting,  it 
ought  to  be  immediately  excited  by  ground  mustard  mixed 
with  warm  water,  or  some  other  active  emetic,  and  after  its 
operation  an  active  purgative  should  be  given.  After  evacuat- 
ing as  much  of  the  poison  as  possible,  strong  coffee  or  vinegar 
and  water  may  be  given  with  advantage. 

Poisonous  Fish.  —  Conger  eel,  mussels,  crabs,  etc. 

ANTIDOTE.  —  Evacuate,  as  soon  as  possible,  the  contents  of 
the  stomach  and  bowels  by  emetics  (ground  mustard  mixed 
with  warm  water  or  powdered  alum)  and  castor  oil,  drinking 
freely  at  the  same  time  of  vinegar  and  water.  Ether,  with 
a  few  drops  of  laudanum  mixed  with  sugar  and  water,  may 
afterward  be  taken  freely. 

Poisonous  Serpents.  —  ANTIDOTE.  —  A  ligature  or  handker- 
chief should  be  applied  moderately  tight  above  the  bite,  and 
a  cupping-glass  over  the  wound.  The  patient  should  drink 
freely  of  alcoholic  stimulants  containing  a  small  quantity  of 
ammonia.  The  physician  may  inject  ammonia  into  the  veins. 

Poisonous  Insects.  —  Stings  of  scorpion,  hornet,  wasp,  bee,  etc. 

ANTIDOTE.  —  A  piece  of  rag  moistened  with  a  solution  of 
carbolic  acid  may  be  kept  on  the  affected  part  until  the  pain 
is  relieved;  and  a  few  drops  of  carbolic  acid  may  be  given 
frequently  in  a  little  water.  The  sting  may  be  removed  by 
making  strong  pressure  around  it  with  the  barrel  of  a  small 
watch-kev. 


354  FIRST  HELP  IN  ACCIDENTS 

QUESTIONS    FOR   TOPICAL    REVIEW 

PAGK 

1.  What  is  a  frequent  accompaniment  of  severe  accidents  ? 342 

2.  What  would  you  do  for  a  person  suffering  from  shock  ?  from  faint- 

ness  ?  from  vertigo  ? 342,  343 

3.  How  would  you  recognize  and  check  arterial  bleeding  ? 343,  344 

4.  What  is  the  difference  between  a  fracture  and  a  dislocation? 344,  345 

5.  What  can  you  do  for  each  until  a  physician  arrives  ? 345 

6.  What  are  the  causes,  symptoms,  and  treatment  of  a  sprain? 346 

7.  What  is  the  treatment  for  burns  and  scalds  ? 346,  347 

8.  What  is  the  treatment  for  asphyxia  from  inhaling  illuminating  gas  ?      347 

9.  What  is  the  best  thing  to  do  when  your  nose  or  ears  are  frost-bitten  ?      348 
10. v  What,  are  the  signs  of  sunstroke,  and  what  would  you  do  for  any 

one  suffering  from  it  ? 348 

11.  What  is  said  about  fits  and  convulsions  ? 348 

12.  Give  a  careful  account  of  the  way  to  treat  a  person  apparently 

drowned  ? 34.9,  350 

13.  Take  up  each  of  the  poisons  mentioned  and  give  its  antidote 350,  354 


CHAPTER  XIV 

BACTERIA  AND  DISEASE 

Bacteria  —  Cause  Disease  —  Require  Warmth  and  Moisture  —  Varieties 
of  Bacteria — Toxines  and  Ptomaines  —  Antitoxine  —  Destruction  of 
Bacteria 

1.  Bacteria.  —  The  term  bacteria  is  applied  to  a  large  num- 
ber of  microscopic  organisms,  found   both  in  the  animal  and 
vegetable  kingdoms.     In  shape  they  are  spherical,  oval,  rod- 
like,  or  spiral,  and  their  size  varies  from  ^3000  to  775-^75-  of  an 
inch  in  breadth,  and  from  grrg-ff  ^°  rrnr  °^  an  incn  in  length. 
They  obtain  their  nourishment  entirely  from  organic  matter, 
which  they   destroy   during  the  continuance   of  their   lives. 
They  are  divided  into  saprophytes  and  parasites ;  the  former 
obtaining  their  nutrition  from  dead  organic  matter,  and  the 
latter  from  living  organic  matter.    Decomposition,  putrefaction, 
and  fermentation  are  the  results  of  the  action  of  saprophytic 
bacteria;    the   action  of   parasitic  bacteria  always   results  in 
disease.     We  thus  see  that  bacteria  may  exercise  both  benign 
and  malignant  influences  in  the  processes  of  life.   The  processes 
of  decomposition  which  we  observe  all  around  us  in  nature 
should  be  called  benign,  because  dead  animal  and  vegetable 
matters  are  thereby  transformed  into  such  chemical  compounds 
as  carbonic  acid  gas,  ammonia,  and  water,  which  may  again  act 
as  nourishment  for  living  plants. 

2.  Bacteria  Cause  Disease.  — The  investigations  into  the  causes 
of  various  diseases,  afflicting  both  man  and  animals,  have  led 
to  the  discovery  of  various  bacteria  as  the  probable  causes ; 

1.  What  are  bacteria  ?    How  do  they  obtain  nourishment  ?    Into  what  classes  are  they 
divided  ?    What  results  from  their  action  ? 

2.  Bacteria  as  the  cause  of  disease  ?    Mode  of  propagation  ? 

355 


356  BACTERIA  AND  DISEASE 

and  the  opinion  held  by  many  of  the  most  noted  investigators 
to-day  is,  that  all  diseases  are  caused  each  by  its  specific  bac- 
terium. The  great  value  of  this  discovery  is  apparent  when 
we  consider  it  in  connection  with  the  prevention  and  cure  of 
diseases. 

The  mode  of  propagation  of  all  bacteria  is  by  a  process  of 
transverse  subdivision,  not  unlike  that  illustrated  in  the  first 
chapter  of  this  book. 

3.  Warmth   and   Moisture.  —  All   bacteria  require  for  their 
existence  both  warmth  and  moisture,  so  that  neither  animal 
nor  vegetable  matter  can  be  decomposed  at  low  temperatures 
or  in  the  absence  of  moisture.     This  is  well   shown   by  the 
fact  that  meat  may  be  kept  indefinitely  in  a  frozen  state.    The 
finding  of  the   absolutely  preserved  body  of  the   Mammoth 
elephant,  frozen  in  the  ice  of  Siberia  for  thousands  of  years, 
is  a  further  illustration  of  the  prevention  of  decay  at  low  tem- 
peratures.    The   preservation   of   meat  by  drying  proves  the 
absence  of  decay  when  no  moisture  is  present. 

4.  Yeast  and  mould  are  examples  of  two  of  the  simpler  bac- 
teria which  are  present  in  the  atmosphere  at  all  times;, each 
seeks  its  own  field  for  nourishment  and  growth.     When  yeast 
germs  find  a  liquid  containing  sugar,  a  process  is  set  up  called 
fermentation.  The  yeast  germs  feeding  on  the  sugar  convert  this 
into  alcohol  and  carbonic  acid  gas,  and  being  thus  nourished, 
rapidly  increase  in  numbers,  so  that  when  all  the  sugar  has 
been  consumed,  and  the  process  of  fermentation  has  ceased, 
we  shall  find  a  large  increase  in  the  yeast. 

Mould  exists  in  many  varieties,  and  may  be  observed  in 
various  colors  and  modes  of  growth  on  decaying  vegetable 
matters. 

5.  If  we  begin  now  the  consideration  of  the  disease-produc- 
ing bacteria,  we  are  confronted  by  a  field  so  vast  that  even  an 
outline  description   cannot  be  given  in  a  work  of  this  kind. 
The  three  main  divisions  of  bacteria  have  received  the  names 
of  micrococci,  bacilli,  and  spirilla.     The  micrococci  comprise 

8.  Warmth  and  moisture  ?    Illustrate  the  principle.    The  Mammoth  elephant  ? 
4.  Yeast  and  mould  ?    Fermentation  ? 
6.  The  three  main  di  viaious  of  bacteria  ? 


BACTERIA  AND  DISEASE  357 

all  those  of  a  spherical  form,  the  bacilli  are  all  oval  or  rod- 
like,  and  the  spirilla  are  either  curved  or  twisted.  The  mode 
of  entrance  of  these  various  bacteria  into  the  human  body 
may  be  by  either  air  or  by  food.  Bacteria,  in  order  to  produce 
disease,  must  find  an  entrance  into  the  tissues  of  the  body  in 
some  way.  By  inhalation,  they  would  be  deposited  in  the 
mouth  or  nose,  or  in  some  other  part  of  the  respiratory  truer ; 
by  food,  they  could  gain  entrance  to  the  mouth,  the  stomach, 
or  the  intestines.  In  contagious  diseases,  the  propagation 
would  be  either  through  breathing  the  atmosphere  of  the  sick- 
room or  through  personal  contact,  in  which  case  the  contagion 
is  probably  conveyed  by  the  hands  to  the  mouth. 

6.  Toxines   and   Ptomaines.  —  As  soon  as  the  bacteria  gain 
entrance  to  the  human  body  in  any  of  the  above  enumerated 
ways,  and  find  a  proper  surface  for  their  development,  they 
live  upon   the   albumen  of  the   tissues  which   they   inhabit. 
Here  again,  as  shown  in  the  yeast  example,  a  rapid  propaga- 
tion takes   place,   and   consequently  a   rapid   spreading  into 
adjacent,  and   even   far   distant,  parts  of  the  body.      Their 
growth  in  the  living  tissues  of  the  human  body  results  in  the 
production  of  poisonous   substances,  called  toxines  and  pto- 
maines ;  to  these  the  symptoms  of  disease  are  ascribed. 

7.  Antitoxine.  —  After  certain  of  the  bacterial  diseases  have 
run  their  course,  and  the  patient  has  recovered,  there  seems  to 
be  established  in  the  body  the  power  to  resist  future  attacks, 
as,  for  instance,  in  cases  of  typhoid  fever,  smallpox,  and  scar- 
let fever.     This  condition   is  explained  by  the  fact  that  the 
bacteria  of  the  disease  have  produced  in  the  blood  a  new  sub- 
stance, which  prevents  a  subsequent  growth  of  the  same  kind 
of  bacteria  in  that  person.     To   this  new  product  has  been 
given  the  name  of  antitoxine,  and  this  method  of  Nature's  for 
protection  against  disease  is  now  utilized  both  in  its  cure  and 
in  its  prevention.     The  period  during  which  any  person  who 
has  had  the  disease  is  protected  from  future  attacks,  varies  in 
different  persons  and  in  different  diseases. 

6.  Toxines  and  ptomaines,  how  produced* 

7.  Antitoxine,  its  nature  and  effect  ? 


358  BACTERIA  AND  DISEASE 

8.  Destruction  of  Bacteria.  —  Not  everybody,  however,  who 
is  exposed  to  these  disease-producing  germs  falls  a  victim  to 
them.  Many  persons  are  continually  exposed  to  contagious 
diseases  and  infections  of  various  kinds,  and  yet  do  not  get  the 
disease.  There  must  then  be  a  natural  mode  of  destroying  the 
bacteria  after  they  find  access  to  the  body.  This  power  of 
destroying  bacteria  is  said  to  exist  in  the  white  cells  of  the 
blood.  In  addition  there  exists,  no  doubt,  in  the  fluid  portion 
of  the  blood,  the  plasma,  a  chemical  power  to  destroy  bacteria. 

8.  The  natural  mode  of  destroying  bacteria  ? 


APPENDIX 

THE  CARE  OF  THE  SICK-ROOM 

THE  sick-room  should  be  bright  and  airy,  and  "sweetness  and 
light"  its  motto.  Other  things  being  equal,  it  is  best  on  one  of  the 
upper  floors — -in  the  case  of  some  "catching"  disease  on  the  top 
floor.  Let  it  be  on  the  sunny  side  of  the  house.  If  for  any  reason 
the  light  of  the  sun  is  temporarily  to  be  avoided  —  as  when  the 
eyes  are  sensitive  or  have  been  operated  upon  —  let  the  light  be  shut 
out  by  a  proper  arrangement  of  blinds  or  curtains.  The  air-supply  to  be 
breathed  by  the  sick  person  should  be  pure.  Those  who,  in  health,  find 
themselves  in  an  impure  air  can  quit  it ;  they  are  not  compelled  to  suffer 
from  it ;  but  a  sick  person  may  be  incapable  of  recognizing  the  bad 
quality  of  the  air,  as  well  as  helpless  to  free  himself  from  it. 

To  keep  the  air  pure,  the  windows  should  be  opened  as  often  as  three 
times  a  day,  care  being  taken  to  protect  the  patient  from  being  chilled, 
while  the  room  is  being  aired. 

Unless  the  physician  should  direct  differently,  one  window — that  most 
remote  from  the  bed  —  should  be  open  an  inch  or  more  both  day  and 
night,  and  in  all  seasons.  The  extent  to  which  the  sash  should  be  lowered 
must  be  governed  largely  by  the  weather  and  the  direction  of  the  wind. 

A  fire,  in  an  open  fireplace,  except  in  summer  weather,  will  be  a  great 
help  towards  keeping  the  air  pure.  The  upward  current  through  a  chim- 
ney-flue, if  unobstructed,  is  equal  to  or  not  far  below  20,000  cubic  feet 
per  hour;  an  outlet  sufficient  for  a  room  occupied  by  ten  persons. 

The  inlet  of  air,  however,  must  not  be  forgotten,  otherwise  the  air  in 
the  room  tends  to  become  both  impure  and  too  thin.  As  our  houses  are 
generally  constructed,  the  inlet  of  air  is  best  secured  by  a  window-sash 
being  lowered  from  the  top. 

Take  special  care  that  no  stationary  wash-basin  or  other  sewer-con- 
nected convenience  is  improperly  plumbed,  and  that  sewer  gas  cannot  by 
any  possibility  escape  into  the  sick-room. 

The  swinging  of  doors  to  create  a  current  is  not  an  efficient  means  of 
ventilation,  as  it  agitates  the  air  of  the  room  without  purifying  it,  and 
often  disturbs  the  patient. 


SCO  APPENDIX 

A  draught  of  air  is  to  be  avoided  ;  it  will  seldom  occur  that  the  air  of 
the  room  requires  to  be  so  speedily  changed  that  the  patient  need  be 
exposed  to  a  draught ;  never,  when  care  has  been  taken  to  provide  con- 
tinuous and  gradual  ventilation, 

It  should  be  borne  in  mind  that  cold  air  is  not  necessarily  pure  air, 
and  that  ventilation  is  not  less  needed  in  winter  than  in  warm  weather. 

Sleep  is  a  great  necessity  to  the  sick.  If  a  well  person  slumbers  in  the 
day-time,  it  will  interfere  with  his  sound  repose  at  night,  but  with  the 
sick  this  is  generally  not  the  case.  The  more  they  sleep  the  more  favor- 
able are  the  chances  for  their  recovery :  so  that  it  will  be  readily  seen 
how  important  it  is  to  avoid  noise  and  jar  in  the  sick-room,  especially  if 
the  disease  is  acute. 

Bear  in  mind  that  even  slight  noises,  as  the  rustling  of  garments,  the 
creaking  of  doors,  whispering,  or  noisy  footfalls,  may  be  sufficient  to  dis- 
turb a  brain  that  is  rendered  sensitive  by  pain  or  wakefulness. 

The  clothing  next  the  skin  should  be  changed  more  frequently  in  sick- 
ness than  in  health.  These  changes  must  be  quickly  and  deftly  made, 
and  with  as  little  disturbance  as  possible. 

Under  some  conditions  of  disease,  the  best  welfare  of  the  patient  is 
accomplished  by  having  two  beds  in  the  room  instead  of  one. 

The  temperature  of  the  room  must  be  watched.  To  that  end  a  ther- 
mometer should  always  be  present,  and  easily  approached.  It  is  better 
not  to  have  it  directly  in  the  view  of  the  patient.  The  temperature 
should  not  be  allowed  to  vary  much  from  65°  F.,  unless  the  doctor  other- 
wise directs. 

Let  the  furniture  be  as  plain  and  as  free  from  upholstery  as  possible  ; 
not  many  pieces  are  required.  Movable  carpets  or  rugs  are  better  than 
those  that  are  permanently  laid.  Curtains  about  the  windows  are  out  of 
place  in  a  sick-room :  so  are  flowering  plants  and  birds,  as  a  general  rule. 
Florence  Nightingale,  however,  makes  an  exception  in  the  case  of  chronic 
invalids,  and  consents  to  the  comforting  influence  of  a  pet  bird  or  two. 

In  regard  to  the  admission  of  visitors,  and  conversation,  much  will 
depend  upon  the  strength  of  the  patient  and  the  kind  of  sickness:  at 
many  times  these  are  to  be  forbidden,  as  having  a  disquieting  influence. 
When  contagious  disease  is  in 'the  house,  the  sick-room  must  be  avoided 
by  all  except  those  who  have  the  care  of  the  patient,  and  those  having 
this  care  should  avoid  coming  in  contact  with  the  other  members  of  the 
household,  especially  the  children. 

Bear  in  mind  that  everything  brought  in  contact  with  the  sick  is  liable 
to  endanger  the  health  of  the  well. 

No  articles  in  use  by  the  invalid  should  be  removed  or  used  by  others 
until  thoroughly  disinfected  ;  the  dishes  and  spoons  should  be  put  in  boil- 
ing water  before  being  taken  from  the  room.  The  room  itself  should  be 
fumigated  with  sulphur  when  the  person  is  removed  from  it 


APPENDIX  361 

Old  pieces  of  muslin,  etc.,  should  be  used  instead  of  handkerchiefs  to 
receive  the  poisonous  discharges  from  the  nose,  mouth,  and  throat. 
These  can  be  destroyed  by  fire,  and  thus  prevent  the  danger  of  conveying 
the  disease  to  others. 

"  Taking  the  breath  "  and  kissing  should  be  avoided  by  those  in  atten- 
dance upon  the  case. 

The  bottles  of  medicine  and  other  reminders  of  illness  should,  as  far 
as  convenient,  be  withdrawn  from  the  view  of  the  sick. 

Such  as  are  to.  be  kept  always  at  hand  should  be  arranged  in  an 
orderly  way  upon  a  tidily- covered  bed-side  table.  The  sight  of  a  siphon 
bottle  of  aerated  water  is  agreeable  to  most  patients ;  that  may  be  kept 
in  the  room,  but  the  vessels  containing  milk,  drinking-water,  etc.,  should 
be  kept  elsewhere. 

DISINFECTION 

Filth  fosters  or  produces  certain  diseases ;  it  should,  therefore,  be 
removed  as  soon  as  possible.  When  it  is  difficult  to  remove  it,  dis- 
infectants come  into  play,  as  they  have  the  power  to  rob  it  of  some  of 
its  disease-breeding  force.  But  let  it  be  remembered  that  disinfection  is  not 
cure  ;  it  is  not  a  substitute  for  cleanliness  and  pure  air.  The  true  cure  is 
the  removal  of  filth  ;  and  when  our  homes  are  concerned  in  some  question 
of  drainage  where  the  filth  is  out  of  our  sight,  it  may  be  necessary  to 
consult  and  employ  the  plumber  or  some  other  artisan. 

In  times  gone  by,  it  was  the  custom  to  mask  bad  smells  by  burning 
pastilles,  coffee,  cascarilla,  and  the  like.  These  are  not  now  much  used; 
for  most  pei-sons  have  come  to  understand  that  the  fumes  thus  created  do 
not  remove,  but  simply  overpower  the  evil  odors. 

Chemistry  has  advanced  to  such  a  point  that  various  pungent  chemical 
substances,  formerly  not  well  known,  can  be  furnished  at  small  cost,  and 
these  substances  have  the  power,  in  varying  degrees,  to  check  vile  odors. 
Carbolic  acid,  chloride  of  lime,  and  Labarraque's  solution  are  among  the 
best  known  of  these,  but  there  are  also  certain  of  the  salts  of  iron,  and 
zinc,  and  permanganate  of  potash  that  may  be  used.  Sulphur  is  much 
used  for  the  fumigation  of  rooms  that  have  been  infected. 

Another  cheap  disinfectant  is  a  solution  of  chloride  of  lead.  It  is  in- 
odorous, effective,  and  the  cost  is  small.  Take  half  a  drachm  of  the 
nitrate  and  dissolve  it  in  a  pint  or  more  of  boiling  water.  Dissolve  two 
drachms  of  common  salt  in  a  pail  or  bucket  of  water  ;  pour  the  two  solu- 
tions together  and  allow  the  sediment  to  sink.  A  cloth  dipped  in  this 
solution,  and  hung  up  in  a  room,  will  correct  a  bad  odor  promptly,  or  if 
the  solution  be  thrown  down  a  drain,  or  upon  foul-smelling  refuse,  it  will 
have  the  same  effect. 

The  room  to  be  purified  with  sulphur  should  be  made  as  tight  as  pos- 
sible, so  that  no  fumes  can  escape,  either  by  window,  door,  or  chimney. 


362  APPENDIX 

Put  three  pounds  of  sulphur  in  an  iron  pot,  which  should  not  stand  upon 
woodwork  or  carpet,  lest  they  be  burned,  but  in  a  large  pan  of  ashes,  or 
upon  a  layer  of  bricks  ;  on  this  sulphur  pour  a  tablespoonful  of  alcohol. 
This  is  then  set  on  fire,  and  everybody  immediately  withdraws  from  the 
room.  The  room  should  remain  closed  ten  hours,  after  which  it  should  be 
thoroughly  aired  before  it  is  occupied,  for  the  fumes  of  the  sulphur  are 
irritating  to  the  lungs. 

The  chemicals  above  mentioned  should  be  known  and  labelled  as 
poisons.  Many  persons  have  been  injured,  if  not  killed,  by  incautiously 
or  ignorantly  drinking  those  that  are  of  a  liquid  form. 

Heat  is  one  of  the  best,  if  not  the  best,  disinfecting  agent.  Articles  of 
bedding  and  furniture  that  cannot  well  "be  treated  otherwise  can  be  puri- 
fied by  a  long  exposure  to  a  temperature  of  240°  F.  In  some  cities,  es- 
pecially in  England,  furnaces  are  made  for  the  reception  of  bulky  articles 
that  have  become  infected. 

Fresh  air" is  another  powerful  agent.  If  woven. fabrics,  clothing,  and 
'  the  like  are  for  a  long  time  aired  out  of  doors,  they  cease  to  be  infective  ; 
probably  by  the  enormous  dilution,  if  not  destruction,  of  the  elements  of 
danger. 

Certain  diseases  are  "catching"  ;  they  have  the  power  of  spreading 
from  one  person  to  another,  chiefly  by  the  particles  that  pass  off  from  the 
body  of  the  patient.  Among  these  diseases  are  small-pox,  measles, 
scarlet  fever,  and  diphtheria.  The  articles  that  are  worn  or  used  by  the 
patient  become  "infected,"  and  they  should  be  disinfected  before  they 
are  used  by  others.  As  a  rule,  of  course,  a  doctor  will  be  called  in  to 
attend  to  these  diseases.  When  that  is  so,  follow  his  directions  as  to  dis- 
infection, as  well  as  every  other  part  of  the  treatment  of  the  case.  For 
substances  that  are  not  injured  by  being  washed,  a  good  and  cheap  dis- 
infectant is  sulphate  of  zinc  ("  white  vitriol")  and  common  salt  dissolved 
in  water,  boiling  hot  if  possible,  using  eight  tablespoonfuls  of  the  zinc 
and  four  of  salt  to  the  gallon  of  water.  This  is  useful  for  clothing,  bed- 
linen,  towels,  handkerchiefs,  etc.  After  these  articles  have  lain  for  an 
hour  or  two  in  this  solution,  they  should  be  allowed  to  stand  in  boiling 
,  water  before  being  washed.  Infected  articles  that  are  of  little  value 
should,  of  course,  be  destroyed  by  fire. 

The  United  States  Treasury  Department  has  published  the  following 
formula  for  the  disinfection  of  the  rags  coming  from  Egypt:  "  1.  Boiling 
in  water  for  two  hours  under  a  pressure  of  fifty  pounds  per  square  inch  ; 
2.  Boiling  in  water  for  four  hours  without  pressure  ;  or,  3.  Subjection  to 
the  action  of  sulphur  fumes  for  six  hours,  burning  one  and  one-half  to 
two  pounds  of  roll-brimstone  in  each  1,000  cubic  feet  of  space,  with  the 
rags  well  scattered  upon  racks."  Any  one  of  these  three  methods  is 
accepted  as  sufficiently  thorough  to  prevent  the  spreading  of  cholera  by 
means  of  rags. 


APPENDIX  363 


THE  HOME  AND  HEALTH 

The  location  of  the  house  should  be  airy,  dry,  and  sunny. 

A  certain  amount  of  elevation  is  necessary,  in  order  to  secure  proper 
drainage.  Too  much  shade  must  not  fall  upon  the  house,  as  sunlight  is 
very  necessary  to  a  proper  degree  of  animal  vigor.  Young  children,  as 
is  well  known,  especially  profit  by  the  tonic  influence  of  sunlight. 

The  cellar  is  an  important  part  of  the  dwelling  ;  therefore,  unless  care 
be  taken  for  its  ample  ventilation,  it  will  be  the  source  from  which  is  sup- 
}  lisd  much  of  the  air  breathed  in  the  upper  chambers  of  the  house.  If 
•lie  cellar  is  damp  the  house  is  liable  to  become  so,  and  if  vegetables  are 
I  tored  in  the  cellar,  an  'especial  degree  of  care  is  needed  to  ventilate  it 
thoroughly  and  constantly. 

House  Drainage.  —  An  English  writer  has  stated  that  "the  most 
important  part  of  the  house  is  the  drains."  This,  no  doubt,  sounds 
i  strangely  to  the  ears  of  many,  who  have  been  brought  up  to  view  the 
parlor  or  drawing-room  as  the  true  centre  of  the  house  ;  and  yet  it  is  no 
foolish  saying,  when  we  reflect  that  with  a  bad  system  of  drainage  to  a 
house  every  dweller  therein  stands  in  peril  of  several  forms  of  disease 
that,  mild  as  the  cases  may  be,  are  a  source  of  anxiety,  and  when  severe, 
too  often  have  a  fatal  termination.  Drain-diseases,  such  as  typhoid 
fever,  dysentery,  diphtheria,  and  scarlet  fever,  often  destroy  entire  fami- 
lies. These  diseases  do  not  always  come  upon  a  home  through  defective 
drainage,  but  when  they  do,  they  frequently  show  themselves  in  a  very 
violent  form. 

Drainage  (as  applied  to  dwellings)  consists  in  conveying  away  from 
the  house  the  liquid  and  solid  impurities  that  would  otherwise  accumulate 
in  or  near  the  dwelling.  Waste  is  a  necessary  accompaniment  of  all 
animal  life,  to  the  preparation  and  taking  of  food,  to  the  clothing  of  the 
body,  to  bathing  and  other  simple  acts  of  daily  life.  The  waste  material 
of  houses  tends  to  decay  and  to  become  offensive.  It  must,  therefore, 
not  only  be  put  out  of  sight  and  smell,  but  must  be  removed  so  far  away 
that  it  cannot  return  in  the  form  of  dangerous,  invisible  gases  of  decom- 
position. 

The  best  house-drains  are  made  of  iron  or  glazed  earthenware,  care- 
fully selected  and  well  laid.  The  joints  of  the  pipes  should  be  gas-tight. 
The  soil-pipe  should  be  carried  up  to  and  through  the  roof.  All  the 
waste-pipes  from  basins,  etc. ,  in  the  rooms  should  be  joined  in  a  gas-tight 
manner  to  the  soil-pipe,  and  each  and  every  basin  and  other  fixture 
should  have  a  separate  trap.  What  is  a  trap?  It  is  a  device  that  is 
designed  to  retain  a  certain  portion  of  the  water  running  through  it  — 
called  the  "  water-seal "  —  so  that  the  ascent  of  air  or  gas,  from  the  drain 
back  into  the  room,  is  prevented.  It  "traps"  the  sewer  gas  away  from 
us.  Whenever  a  fixture  has  been  used  and  there  is  not,  beyond  all 


364  APPENDIX 

doubt,  a  sufficiency  of  water  to  fill  the  trap,  additional  water  should  be 
poured  in.  Traps  are  of  various  sizes,  and  of  an  infinite  variety  of  pat- 
terns and  patents,  and  must  vary  greatly  according  to  their  situation  ; 
but  one  thing  should  be  made  sure  of  in  their  use  —  namely,  that  they 
hold  not  less  than  two  inches  of  water  as  a  "  seal." 

There  is  at  almost  all  seasons  of  the  year  an  upward,  because  warmer, 
current  of  air  through  the  main  pipes.  It  is  therefore  better  to  have  a 
fresh-air  inlet  pipe  near  the  point  where  the  drain  leaves  the  house- wall. 
This  helps  to  prevent  the  unsealing  of  traps.  It  also  brings  about  a 
purer  condition  of  the  air  in  the  interior  of  the  system  of  pipes  —  so  use- 
ful in  this  air-current  through  the  soil-pipe  that  if  applied  there  is  little 
danger  of  the  escape  of  sewer  gas  into  the  living  rooms. 

What  is  sewer  gas  or  sewer  air  ?  It  varies  greatly  in  different  places 
and  at  different  times.  It  is  not  a  definite  gas,  like  oxygen,  nitrogen, 
etc.,  but  varies  .in  composition,  and  what  is  still  more  worthy  of  note,  it 
varies  in  its  dangerous  qualities.  It  is  not  always  offensive,  although  it 
is  generally  so  ;  its  odor  has  been  described  as  being  "  sweetish  and  sick- 
ish."  Its  dangerous  qualities  have  not  yet  been  determined  by  chemistry 
or  the  microscope,  but  one  practical  point  may  be  borne  in  mind  — 
namely,  that  when  a  case  or  cases  of  contagious  disease  occur  in  any 
hoTjse  along  any  given  line  of  sewer  pipes,  it  is  best  to  use  disinfectants 
in  the  drainage  of  the  other  dwellings  along  the  same  line  of  sewer. 
Children  should  avoid  playing  over  or  around  the  sewer-gratings  in  the 
streets  at  all  times,  and  especially  when  scarlet  fever  and  like  contagious 
diseases  are  known  to'  be  in  the  neighborhood ;  for  the  exit  of  sewer  air 
at  these  points  is  always  very  free,  unless  it  be  directly  after  rainfall. 

One  other  point  must  be  remembered  —  that  the  best-laid  system  of 
house-plumbing  is  not  indestructible.  In  the  course  of  time,  defects  will 
arise,  breaks  will  occur  ;  for  this  reason  it  would  be  well  for  every  house- 
holder to  have  an  examination  made  at  intervals,  of  every  joint  and  along 
the  whole  line  of  the  house  connection  with  the  sewer  or  drain. 

It  is  thought  by  many  that  sewer  gas  is  not  found  in  the  country 
because  there  are  no  sewers  —  they  have  been  misled  by  the  word.  If 
the  words  "drain  air"  or  "filth  gas"  had  been  adopted,  the  universal 
production  of  this  injurious  substance,  in  close  connection  with  every 
abode  of  man,  wherever  located,  might  have  been  better  understood.  In 
country  houses  there  are,  perhaps,  fewer  dangers  of  contamination  of  the 
air  we  breathe  by  waste  products,  because  there  are  fewer  water-closets, 
wash-basins,  sinks,  etc. ,  and  the  rooms  are  less  exposed  to  impure  air. 

But  in  the  country  danger  is  apt  to  come  by  or  through  the  pollution 
of  the  water  supply.  The  well,  which  furnishes  that  cool  and  refreshing 
draught,  is  the  point  to  be  watched.  It  is  convenient  to  have  the  well  near 
the  house,  because  when  the  snow  is  on  the  ground  and  the  weather  is 
cold,  the  distance  to  the  well  from  the  house  is  a  matter  of  no  small 


APPENDIX  365 

moment.  Near  the  house  must  be  the  stable  and  pens  for  animals  —  the 
waste  from  the  house  goes  upon  the  ground,  and  not  very  far  away  from 
the  house  —  the  chamber  slops  and  the  more  offensive  matters  go  into 
a  pit,  which  must  not  be  too  distant.  The  result  of  all  these  conditions 
is  a  pollution  of  the  soil  at  all  these  points  —  a  pollution  which  spreads 
with  every  rainfall,  and  which,  sooner  or  later,  reaches  the  well ;  yet  the 
water  may  appear  as  pure  as  ever.  It  only  remains  to  have  the  suitable 
disease-germ  lodged  in  this  polluted  territory  to  bring  down  the  whole 
household  with  a  fever.  This  is  the  kind  of  soil-pollution  which  is  hard 
to  cure,  and  which,  in  long-settled  countries,  causes  laws  to  be  enacted 
requiring  all  vaults  for  the  reception  of  house  and  human  waste  to  be 
made  water-tight,  so  as  to  save  the  soil  from  its  poisoning  influence. 

This  is  the  kind  of  poisoning  which,  in  the  Dark  Ages,  caused  so  much 
unrighteous  persecution  of  the  innocent.  In  those  days,  no  care  whatever 
was  taken  in  the  towns,  high-walled,  crowded,  and  unsewered,  to  protect 
the  water  supply  from  pollution  —  as  a  result,  some  terrible  epidemic  of 
fever  would  arise.  Then  the  angry  populace  would,  in  their  ignorance, 
cry  out :  u  The  Jews  have  poisoned  the  wells."  The  wells  were  poisoned, 
no  doubt,  but  the  Jew  was  no  more  worthy  of  blame  than  were  his  ac- 
cusers. Nevertheless,  the  Jews  were  not  spared  —  they  were  robbed, 
imprisoned,  executed.  ' 

Drainage  in  the  city  is  a  comparatively  easy  problem  when  the  city's 
sewers  are  laid  in  the  streets.  In  the  country  it  is  more  difficult,  and  on 
this  account  the  fewer  fixtures  or  u  modern  improvements  "  there  are  in 
the  house  the  better  it  will  be.  There  should  be  no  less  care  within  the 
country  house,  where  waste-pipes  are  put  in,  than  in  the  city  house.  The 
material  should  be  well  selected,  tightly  joined,  and  properly  ventilated. 
The  water-closet  should  be  remote  from  the  house.  Earth  closets  are 
better  than  the  ordinary  vaults  —  house-waste  from  kitchen  and  laundry 
should  be  taken  to  a  considerable  distance  from  the  house,  and  far  away 
from  the  well,  and  either  deposited  in  a  water-tight  cesspool,  or  conveyed 
away,  by  a  system  of  subsoil  drainage  tiles,  arranged  so  as  to  fertilize 
some  unoccupied  plot  of  ground. 

ON  GOING  INTO  THE  COUNTRY 

To  spend  the  summer  in  the  country  would  be  the  choice  of  all  city 
dwellers,  whenever  their  purses  will  permit  of  it.  And  there  are  not  a 
few  advantages  in  such  a  course  ;  the  change  of  scene  is  good,  the  moun- 
tains and  the  seaside  give  a  purer  and  cooler  air —  an  air  that  invigorates 
and  aids  in  restful  sleep  at  night,  so  different  from  the  midsummer  atmos- 
phere in  hot  cities.  There  are  fewer  excitements  in  the  country  ;  we  do 
not  "  live  so  fast,"  and  there  is  full  scope  for  healthful  life  and  activity  in 
the  open  air,  with  the  green  and  blue  of  nature  all  about  us,  instead  of 
the  monotonous  walls  of  towering  houses. 


366  APPENDIX 

But  this  course,  pleasant  and  helpful  to  so  many,  is  not  without  its 
danger.  Many  who  go  away  for  a  vacation  are  brought  home  sick  on 
account  of  fever  or  other  sickness  caused  by  defects  and  faults  of  drain- 
age existing  in  these  temporary  summer  homes.  Scarcely  a  year  goes  by 
that  one  or  more  summer  resorts  have  not  gained  the  ill  name  of  being 
the  hotbeds  of  typhoid  fever,  dysentery,  and  the  like. 

In  view  of  this,  how  important  it  becomes  that  we  exercise  judgment, 
and  seek  skilled  advice  in  the  selection  of  our  summering  places. 

Again,  there  is  another  danger  that  must  not  be  overlooked.  Let  us 
suppose  that  the  summer  vacation  has  passed  by  without  accident ;  that 
we  return  invigorated  by  the  experience,  and  that  the  home  in  the  city 
has  been  empty  and  closed  during  our  absence  ;  what  has  happened  that 
the  air  in  the  rooms  newly  reopened  should  be  foul  and  stifling  ?  This 
has  taken  place :  the,  water  that  stands  in  the  traps  of  house  pipes,  and 
shuts  off  gases  from  the  sewer  when  the  rooms  are  in  use  and  water  is 
daily  entering  the  different  wash-basins,  etc. ,  has  during  our  absence  been 
evaporated.  For  weeks,  perhaps,  there  has  been  no  "  water-seal  "  in  the 
traps,  and  the  ascent  of  sewer  air  has  been  going  on  continuously,  so  that 
not  only  is  the  air  utterly  unfit  to  live  in,  but  all  the  curtains,  carpets,  and 
other  absorbing  materials  have  become  saturated  with  the  pollution  thus 
allowed  to  enter.  Let  it  be  remembered  that  when  a  sink,  etc.,  is  not  in 
use,  it  is  gradually  losing  the  trap-water  by  the  evaporation. 

What  is  the  remedy,  you  will  ask,  for  the  condition  of  things  caused  by 
closing  up  the  house,  as  above  stated  ?  To  this  the  reply  is,  that  the  house 
should  from  time  to  time  be  opened  and  aired,  and  water  should  be  poured 
down  each  and  every  sanitary  fixture,  in  sufficient  quantity  to  renew  the 
supply  of  water  in  the  trap  of  each. 


APPENDIX 


367 


EXERCISES   FOR  HOME  GYMNASTICS 

(See  page  45) 


FIG.  1.  —  POSITION  FOB  EXERCISING 


FIG.  2. — To  DEVELOP  MUSCLBS  ACROSS 
THE  UPPER  BACK 


^ ^ 


FIG.  3.— To  DEVELOP  FRONT  ARM,  CHEST, 
ABDOMEN,  FRONT  LEG 


FIG.  4.  —  To  DEVELOP  LOWER  BACK 
AND  MIDDLE  BACK 


NOTE.  — The  cuts  of  the  above  illustrations  were  kindly  furnished  by  the  Narragansett 
Machine  Company,  manufacturers  of  the  apparatus,  Providence,  E.I. 


368 


APPENDIX 


FIG.  5.— To  DEVELOP  BACK  UPPEB 


FIG.  6.  —  To  DEVELOP  CHEST  MVSCL.ES 
AND  FKONT  ABM 


FIG.  7. — To  DEVELOP  SIDE- WAIST 
MUSCLES 


FIG.  8. —  To  DEVELOP  UPPER  AND 
LOWER  BACK,  SHOULDER,  BACK 
AKM,  AND  BACK  LEG 


APPENDIX 


369 


FIG.  9.  —  To  DEVELOP  ABDOMEN;  TO  DEEPEN  THE  THOBAX 


FlG.   10. —TO   WIDEN  THE  TuOBAX   AND   DEVELOP  THE  SlDES   OF  WAIST 


FlO.  11. — To   DEVELOP  THE  ABDOMINAL   MtTSCLES   AND    THE   McSCLES   OF   UPPER  LEO 


GLOSSARY 


Ab-do'men  (Latin  abdo,  to  conceal).  The  largest  cavity  of  the  body, 
containing  the  liver,  stomach,  intestines,  etc.  ;  the  belly. 

Ab-sor'bents  (L.  ab  and  sorbeo,  to  suck  up).  The  vessels  which  take 
part  in  the  process  of  absorption. 

Ab-sorp'tion.  The  process  of  sucking  up  fluids  by  means  of  an  animal 
membrane. 

Ac-com-mo-da'tion  of  the  eye.  The  alteration  in  the  shape  of  the  crys- 
talline lens,  which  accommodates  or  adjusts  the  eye  for  near  and 
remote  vision. 

Ac'id,  Lactic  (L.  Zac,  milk).  The  acid  ingredient  of  sour  milk  ;  the  gas- 
tric juice  also  contains  it. 

Al-bu'men,  or  Albumin  (L.  albus,  white).  An  animal  substance  resem- 
bling white  of  egg. 

Al-bu'mi-nose  (from  albumen).  A  soluble  animal  substance  produced 
in  the  stomach  by  the  digestion  of  the  albuminoid  substances. 

Al-bu'min-oid  substances.  A  class  of  proximate  principles  resembling 
albumen ;  they  may  be  derived  from  either  the  animal  or  vegetable 
kingdoms. 

Al'i-ment  (L.  aZo,  to  nourish).     That  which  affords  nourishment ;  food. 

Al-i-ment'ary  Ca-nal  (from  aliment).  A  long  tube  in  which  the  food  is 
digested,  or  prepared  for  reception  into  the  system. 

An-ses-thet'ics  (Greek  av,  an,  without,  aiffdrjela,  aisthesia,  feeling). 
Those  medicinal  agents  which  prevent  the  feeling  of  pain,  such  as 
chloroform,  laughing-gas,  etc. 

An-i-mal'cule  (L.  animal' culum,  a  small  animal).  Applied  to  animals 
which  can  only  be  seen  with  the  aid  of  the  microscope.  Animalculum 
(plural,  animalcula)  is  used  with  the  same  meaning. 

A-or'ta  (Gr.  dopr^o/xat,  aorteomai,  to  be  lifted  up).  The  largest  artery  of 
the  body,  and  main  trunk  of  all  the  arteries.  It  arises  from  the  left 
ventricle  of  the  heart.  The  name  was  first  applied  to  the  two  large 
branches  of  the  trachea,  which  appear  to  be  lifted  up  by  the  heart. 

A'que-ous  Humor  (L.  aqua,  water).  A  few  drops  of  watery  colorless 
fluid  occupying  the  space  between  the  cornea  and  crystalline  lens. 

A-rach'noid  Mem'brane  (Gr.  dpdxvr)>  arachne,  a  cobweb,  and  et'Sos,  eidos, 

370 


GLOSSARY  371 

like).     An  extremely  thin  covering  of  the  brain  and  spinal  cord.     It 

lies  between  the  dura  mater  and  the  pia  mater. 
Ar'bor  Vi'tae  (L).     Literally,  "the  tree  of  life";  a  name  given  to  the 

peculiar  appearance  presented  by  a  section  of  the  cerebellum. 
Ar'ter-y  (Gr.  d^p,  aer,  air,  and  r-fipeiv,  terein,  to  contain).     A  vessel  by 

which  blood  is  conveyed  away  from  the  heart.     It  was  supposed  by 

the  ancients  to  contain  air ;  hence,  the  name. 
Ar-tic-u-la'tion  (L.  articulo,  to  form  a  joint).     The  more  or  less  movable 

union  of  bones,  etc.;  a  joint. 
A-ryt'e-noid  Car'ti-la-ges  (Gr.  dpvTaiva,  arutaina,  a  pitcher).     Two  small 

cartilages  of  the  larynx,  resembling  the  mouth  of  a  pitcher. 
As-sim-i-la'tion  (L.  ad,  to,  and  similis,  like).     The  conversion  of  food 

into  living  tissue. 

Au-di'tion  (L.  audio,  to  hear).     The  act  of  hearing  sounds. 
Au'di-to-ry  Nerve.    One  of  the  cranial  nerves ;  it  is  the  special  nerve 

of  hearing. 

Au'ri-cle  (L.  awn's,  the  ear).     A  cavity  of  the  heart. 
Bar'i-tone  (Gr.  /Saptfs,  barus,  heavy,  and  rbvos,  tonos,  tone).    A  variety  of 

male  voice  between  the  bass  and  tenor. 
Bel-la-don'na  (It.  beautiful  lady).     A  vegetable  narcotic  poison.    It  has 

the  property  of  enlarging  the  pupil,  and  thus  increasing  the  brilliancy 

of  the  eye  ;  so  called  from  its  use  by  Italian  ladies. 
Bi-cus'pid   (L.    6z,   two,   and  cuspis,   prominence).     The  name  of  the 

fourth   and  fifth  teeth  on  each   side    of   the   jaw;    possessing  two 

prominences. 
Bile.    The  gall,  or  peculiar  secretion  of  the  liver;  a  viscid,  yellowish 

fluid,  and  very  bitter  to  the  taste. 
Bron'chi  (Gr.  /3/)67xos,  bronchos,  the  windpipe).    The  two  first  divisions 

or  branches  of  the  trachea  ;  one  enters  each  lung. 

Bron'chi-al  Tubes.    The  smaller  branches  of  the  trachea  within  the  sub- 
stance of  the  lungs,  terminating  in  the  air-cells. 
Bron-chi'tis  (from  bronchia,  and  itis,  a  suffix  signifying  inflammation). 

An  inflammation  of  the  larger  bronchial  tubes;  a  "cold"  affecting 

the  lungs. 

Cal-ca're-ous  (L.  calx,  lime).     Containing  lime. 
Ca-nal'  (L.).     In  the  body,  any  tube  or  passage. 
Ca-nine'  (L.  canis,  a  dog).    Name  given  to  the  third  tooth  on  each  side  of 

the  jaw ;  in  the  upper  jaw  it  is  also  known  as  the  eye-tooth,  pointed 

like  the  tusks  of  a  dog. 
Cap'il-la-ry  (L.   capil'lus,  a  hair,  capilla'ris,  hair-like).     The  name  of 

the  extremely  minute  blood-vessels  which  connect  the  arteries  with 

the  veins. 

Car'bon  Di-ox'ide  (CO2).     Chemical  name  for  carbonic  acid  gas. 
Car-bon'ic  A'cid.    The  gas  which  is  present  in  the  air  expired  from  the 


372  GLOSSARY 

lungs ;  a  waste  product  of  the  animal  kingdom,  and  a  food  of  the 

vegetable  kingdom. 
Car'di-ac  (Gr.  Kapdta,  kardia,  the  heart).     The  cardiac  orifice  of  the 

stomach  is  the  upper  one,  and  is  near  the  heart;  hence  its  name. 
Car-niv'or-ous  (L.  ca'ro,  flesh,  and  vo'ro,  to  devour).   Subsisting  upon  flesh. 
Ca-rot'id  Ar'ter-y.    The  large  artery  of  the  neck,  supplying  the  head 

and  brain. 
Car'ti-lage.    A  solid  but  flexible  material,  forming  a  part  of  the  joints, 

air-passages,  nostrils,  etc. ;  gristle. 
Ca'se-ine  (L.  ca'seus,  cheese).     The  albuminoid  substance  of  milk;  it 

forms  the  basis  of  cheese. 
Cer-e-bel'lum  (diminutive  for  cer'ebrum,  the  brain).     The  little  brain, 

situated  beneath  the  posterior  third  of  the  cerebrum. 
Cer'e-brum  (L.).     The  brain  proper,  occupying  the  entire  upper  portion 

of  the  skull.    It  is  nearly  divided  into  two  equal  parts,  called  "hemi- 
spheres," by  a  cleft  extending  from  before  backward. 
Cho'roid  (Gr.  xfyuo)'»  chorion,  a  membrane  or  covering).    The  middle 

tunic  or  coat  of  the  eyeball. 
Chyle  (Gr.  x^fc,  chulos,  juice).     The  milk-like  fluid  formed  by  the 

digestion  of  fatty  articles  of  food  in  the  intestines. 
Chyme  (Gr.  xujc6s,  chumos,  juice).    The  pulpy  liquid  formed  by  digestion 

within  the  stomach. 

Cil'i-a   (pi.   of  cil'i-um,  an  eyelash).     Minute,  vibratile,   hair-like  pro- 
cesses found  upon  the  cells  of  the  air-passages,  and  other  parts  that 

are  habitually  moist. 
Cir-cu-la'tion  (L.  cir'culus,  a  ring).    The  circuit,  or  course  of  the  blood 

through  the  blood-vessels  of  the  body,  from  the  heart  to  the  arteries, 

through  the  capillaries  into  the  veins,  and  from  the  veins  back  to 

the  heart. 
Co-ag-u-la'tion   (L.   coag'ulo,   to  curdle).     Applied  to  the  process  by 

which  the  blood  clots  or  solidifies. 

Coch'le-a  (L.  coch'lea,  a  snail-shell) .    The  spiral  cavity  of  the  internal  ear. 
Con'cha  (Gr. Kbvxr),  konche,  a  mussel-shell).    The  external  shell-shaped 

portion  of  the  external  ear. 
Con-junc-ti'va  (L.  con  and  jun'go,  to  join  together).     A  thin  layer  of 

mucous  membrane  which  lines  the  eyelids  and  covers  the  front  of  the 

eyeball ;  thus  joining  the  latter  to  the  lids. 
Con-trac-til'i-ty  (L.  con  and  tra'ho,  to  draw  together).    The  property  of 

muscle  which  enables  it  to  contract,  or  draw  its  extremities  closer 

together. 
Con-vo-lu'tions   (L.   con  and  vol'vo,   to   roll  together).     The  tortuous 

foldings  of  the  external  surface  of  the  brain. 

Con-vul'sion  (L.  convel'lo,  to  pull  together).    A  more  or  less  violent  agi- 
tation of  the  limbs  or  body. 


GLOSSARY  373 

Cor'ne-a  (L.  cor'nu,  a  horn).    The  transparent,  horn-like  substance  which 

covers  the  anterior  fifth  of  the  eyeball. 
Cor'pus-cles,  Blood  (L.  dim.  of  cor'pus,  a  body).     The  small  bi-concave 

discs  which  give  to  the  blood  its  red  color ;  the  white  corpuscles  are 

globular  and  larger. 
Cos-met'ic  (Gr.   /coo-^w,  kosmeo,  to  adorn).     Beautifying ;   applied  to 

articles  which  are  supposed  to  increase  the  beauty  of  the  skin,  etc. 
Cra'ni-al  (L.  cra'nium,  the  skull).     Pertaining  to  the  skull.     The  nerves 

which  arise  from  the  brain  are  called  cranial  nerves. 
Cri'coid  (Gr.  /tpfoos,  kri'kos,  a  ring).    A  cartilage  of  the  larynx  resembling 

a  seal-ring  in  shape. 
Crys'tal-line  Lens  (L.  crystal'lum,   a  crystal).     One  of  'the  so-called 

humors  of  the  eye  ;  a  double  convex  body  situated  in  the  front  part  of 

the  eyeball. 
Cu'ti-cle  (L.  dim.  of  cu'tis,  the  skin).     The  scarf-skin ;  also  called  the 

epider'mis. 
Cu'tis  (L.  skin  or  hide).    The  true  skin,  lying  beneath  the  cuticle  ;  also 

called  the  der'mis. 
De-cus-sa'tion  (L.  decus'sis,  the  Roman  numeral  ten,  X).    A  reciprocal 

crossing  of  fibres  from  side  to  side. 
Di'a-phragm  (Gr.  5ia0/«£<r<7u>,  diaphrasso,  to  divide  by  a  partition).     A 

large,  thin  muscle  which  separates  the  cavity  of  the  chest  from  the 

abdomen  ;  a  muscle  of  respiration. 
Dif-fu'sion  of  Gases.     The  power  of  gases  to  become  intimately  mingled, 

without  reference  to  the  force  of  gravity. 
Duct  (L.  du'co,  to  lead)-.     A  narrow  tube  ;  the  thoracic  duct  is  the  main 

trunk  of  the  absorbent  vessels. 

Du-o-de'num  (L.  duode'ni,  twelve).    The  first  division  of  the  small  intes- 
tines, about  twelve  fingers'  breadth  long. 
Du'ra  Ma'ter  (L.).     Literally,  the  hard  mother;  the  tough  membrane 

which  envelops  the  brain. 

Dys-pep'si-a  (Gr.  5us,  dws,  difficult,  and  Tre'Trrw,  pepto,  to  digest).    Diffi- 
cult or  painful  digestion  ;  a  disordered  condition  of  the  stomach. 
E-mul'sion  (L.  emuVgeo,  to  milk).     Oil  in  a  finely  divided  state  sus- 
pended in  water. 
En-am'el  (Fr.  email).    The  dense  material  which  covers  the  crown  of 

the  tooth. 
Endocardium  (Gr.  <?»/5o,  endo,  within,  and  *cap5/a,  kardia,  the  heart.     The 

lining  membrane  of  the  heart. 
En'er-gy,  Specific,  of  a  Nerve.     When  a  nerve  of  special  sense  is  excited, 

whatever  be  the  cause,  the  sensation  experienced  is  that  peculiar  to 

the  nerve ;  this  is  said  to  be  the  law  of  the  specific  energy  of  the 

nerves. 
Ep-i-glot'tis  (Gr.  tvi,  epi,  upon,  and  yXuTTts,  glottis,  the  entrance  to  the 


374  GLOSSARY 

windpipe).     A  leaf -shaped  piece  of  cartilage  which  covers  the  top  of 

the  larynx  during  the  act  of  swallowing. 
Ex-cre'tion  (L.  excer'no,  to  separate).    The  separation  from  the  blood  of 

the  waste  particles  of  the  body  ;  also  the  materials  excreted. 
Ex-pi-ra;tion  (L.  expi'ro,  to  breathe  out).     The  act  of  forcing  air  out  of 

the  lungs. 
Ex-ten'sion  (L.  ex,  out,  and  ten' do,  to  stretch).     The  act  of  restoring  a 

limb,  etc. ,  to  its  natural  position  after  it  has  been  flexed,  or  bent ;  the 

opposite  of  Flexion. 
Fe-nes'tra  (L.).     Literally,  a  window  j  the  opening  between  the  middle 

and  internal  ear. 
Fi'brine  (L.  -ft bra,  a  fibre).     An  albuminoid  substance  found  in  the 

blood  ;  in  coagulating  it  assumes  a  fibrous  form. 
Flex'ion  (L.flecto,  to  bend).     The  act  of  bending  a  limb,  etc. 
Fol'li-cle  (L.  dim.  of  fol'lis,  a  bag).    A  little  pouch  or  depression  in  a 

membrane  ;  it  has  generally  a  secretory  function. 
Fun'gous  Growths  (L.  fun'gus,  a  mushroom).     A  low  grade  of  vegetable 

life. 
Gan'gli-on  (Gr.  ydyy\iov,  ganglion,  a  knot).    A  knot-like  swelling  in  the 

course  of  a  nerve  ;  a  smaller  nerve-centre. 

Gas'tric  (Gr.  ya<rT-/ip,  gaster,  stomach).     Pertaining  to  the  stomach. 
Gland  (L.  glans,  an  acorn).    An  organ  consisting  of  follicles  and  ducts, 

with  numerous  blood-vessels  interwoven  ;  it  separates  some  particular 

fluid  from  the  blood. 
Glos'so-phar-yn-ge'al  Nerve  (Gr.  y\u<r<ra,  glossa,  the  tongue,  and  (pdpvy£, 

pharunx,  the  throat).     The  nerve  of  taste  supplying  the  posterior  third 

of  the  tongue  ;  it  also  supplies  the  throat. 
Glu'ten  (L.).     Literally,  glue  ;   the  glutinous  albuminoid  ingredient  of 

wheat. 
Gran'ule  (L.  dim.  of  gra'num,  a  grain).     A  little  grain ;  a  microscopic 

object. 

Gus-ta'tion  (L.  gusto,  to  taste).     The  sense  of  taste. 
Gust'a-to-ry  Nerve.    The  nerve  of  taste  supplying  the  front  part  of  the 

tongue,  a  branch  of  the  "  fifth  "  pair. 
Hem'or-rhage  (Gr.  afyia,  hai'ma,  blood,  and  ptfywfu,  regnumi,  to  burst). 

Bleeding,  or  the  loss  of  blood. 
Hem-i-ple'gi-a  (Gr.  ^/u<rus,  hemisus,  half,  and  ?rX^(r<ra>,  plesso,  to  strike). 

Paralysis,  or  loss  of  power,  affecting  one  side  of  the  body. 
Hem'i-spheres  (Gr.  <r0cu/oa,  sphaira,  a  sphere).     Half  a  sphere,  the  lateral 

halves  of  the  cerebrum,  or  brain  proper. 

He-pat'ic  (Gr.  yirap,  hepar,  the  liver).     Pertaining  to  the  liveri 
Her-biv'o-rous  (L.  her'ba,  an  herb,  and  vo'ro,  to  devour).     Applied  to 

animals  that  subsist  on  vegetable  food. 
Hu'mor  (L.).    Moisture:   the  humors  are  transparent  contents  of  the 

eyeball. 


GLOSSARY  375 

Hy-dro-phoTn-a  (Gr.  JSwp,  hitdor,  water,  and  <t>optw,phobeo,  to  fear).  ,A 
disease  caused  by  the  bite  of  a  rabid  dog  or  other  animal.  In  a  person 
affected  with  it,  convulsions  are  occasioned  by  the  sight  of  a  glittering 
object,  like  water,  by  the  sound  of,  running  water,  and  by  almost  any 
external  impression. 

Hy'gi-ene  (Gr.  vylcta,  hugieia,  health).  The  art  of  preserving  health  and 
preventing  disease. 

Hy'per-o'pi-a.  Abbreviated  from  Hy'per-me-tro'pi-a  (Gr.  virfy,  huper, 
beyond,  utrpov,  metron,  the  measure,  and  oty,  ops,  the  eye).  A  defect 
of  vision  dependent  upon  a  too  short  eyeball ;  so  called  because  the 
rays  of  light  are  brought  to  a  focus  at  a  point  behind  the  retina ;  the 
true  "far  sight." 

In-ci'sor  (L.  inci'do,  to  cut).  Applied  to  the  front  teeth  of  both  jaws, 
which  have  sharp  cutting  edges. 

In'cus  (L.).     An  anvil ;  the  name  of  one  of  the  bones  of  the  middle  ear. 

In-sal-i-va'tion  (L.  fn,  and  sa-li'va,  the  fluid  of  the  mouth).  The  min- 
gling of  the  saliva  with  the  food  during  the  act  of  chewing. 

In-spi-ra'tion  (L.  iw,  and  spi'ro,  to  breathe).  The  act  of  drawing  in  the 
breath. 

In-teg'u-ment  (L.  in,  and  te'go,  to  cover).  The  skin,  or  outer  covering 
of  the  body. 

In-tes'tine  (L.  in'tus,  within).  The  part  of  the  alimentary  canal  which 
is  continuous  with  the  lower  end  of  the  stomach  ;  also  called  the  intes- 
tines, or  the  bowels. 

I'ris  (L.  i'ris,  the  rainbow).  The  thin  muscular  ring  which  lies  between 
the  cornea  and  crystalline  lens,  and  which  gives  the  eye  its  brown, 
blue,  or  other  color. 

Ju'gu-lar  (L.ju'gulum,  the  throat).  The  name  of  the  large  veins  which 
run  along  the  front  of  the  neck. 

Lab'y-rinth  (\apvpivdos,  laburin'thos,  a  building  with  many  winding  pas- 
sages). The  very  tortuous  cavity  of  the  inner  ear,  comprising  the 
vestibule,  semi-circular  canals,  and  the  cochlea. 

Lach'ry-mal  Apparatus  (L.  lach'ryma,  a  tear).  The  organs  for  forming 
and  conveying  away  the  tears. 

Lac'te-als  (L.  Zac,  lac'tis,  milk).  The  absorbent  vessels  of  the  small 
intestines  ;  during  digestion  they  are  filled  with  chyle,  which  has  a 
milky  appearance. 

La-ryn' go-scope  (Gr.  \dpvy£,  larunx,  the  larynx,  and  <r/coir^w,  skopeo,  to 
look  at).  The  instrument  by  which  the  larynx  may  be  examined  in 
the  living  subject. 

Lar'ynx  (Gr.)  The  cartilaginous  tube  situated  at  the  top  of  the  wind- 
pipe, or  trachea  ;  the  organ  of  the  voice. 

Lens  (L.)  Literally,  a  lentil ;  a  piece  of  transparent  glass  or  other  sub- 
stance so  shaped  as  either  to  converge  or  disperse  the  rays  of  light. 


376  GLOSSARY 

Lig'a-ment  (L.  Wgo,  to  bind).    A  strong,  fibrous  material  binding  bones 

or  other  solid  parts  together  ;  it  is  especially  necessary  to  give  strength 

to  joints. 
Lig'a-ture.    A  thread  of  silk  or  other  material  used  in  tying  around  an 

artery. 
Lymph  (L.  lym'pha,  spring-water).     The  colorless,  watery  fluid  conveyed 

by  the  lymphatic  vessels. 

Lym-phat'ic  Vessels.    A  system  of  absorbent  vessels. 
Mal'le-us  (L.).     Literally,  the  mallet ;  one  of  the  small  bones  of  the  mid- 
dle ear. 
Mar'row.    The  soft,  fatty  substance  contained  in  the  central  cavities  of 

the  bones  :  the  spinal  marrow,  however,  is  composed  of  nervous  tissue. 
Mas-ti-ca'tion  (L.  mas'tico,  to  chew).     The  act  of  cutting  and  grinding 

the  food  to  pieces  by  means  of  the  teeth. 
Me-dul'la  Ob-lon-ga'ta.     The  "  oblong  marrow,"  or  nervous  cord,  which 

is  continuous  with  the  spinal  cord  within  the  skull. 
Mem-bra'na  Tym/pan-i  (L. ) .     Literally,  the  membrane  of  the  drum ;  a 

delicate  partition  separating  the  outer  from  the  middle  ear ;  it  is 

sometimes1  incorrectly  called  the  drum  of  the  ear. 
Mem'brane.     A  thin  layer  of  tissue  serving  to  cover  some  part  of  the 

body. 
Mi'cro-scope  (Gr.  /U/C/DO'S,  micros,  small,  and  O-KOTT^U,  skopeo,  to  look  at). 

An  optical  instrument  which  assists  in  the  examination  of  minute 

objects. 
Mo'lar  (L.  mo'la,  a  mill).     The  name  applied  to  the  three  back  teeth 

of  each  side  of  the  jaw  ;  the  grinders,  or  mill-like  teeth. 
Mo'tor  (L.  mo'veo,  mo'tum,  to  move).     Causing  motion ;  the  name  of 

those  nerves  which  conduct  to  the  muscles  the  stimulus  which  causes 

them  to  contract. 

Mu'cous  Mem'brane.    The  thin  layer  of  tissue  which  covers  those  inter- 
nal cavities  or  passages  which  communicate  with  the  external  air. 
Mu'cus.     The  glairy  fluid  which  is  secreted  by  mucous  membranes,  and 

which  serves  to  keep  them  in  a  moist  condition. 
My-o'pi-a  (Gr.  ^uo>,  wwo,  to  contract,  and  w^,  ops,  the  eye).    A  defect  of 

vision  dependent  upon  an  eyeball  that  is  too  long,  rendering  distant 

objects  indistinct ;  near-sight. 
Na'sal  (L.  na'sus,  the  nose).    Pertaining  to  the  nose  ;  the  nasal  cavities 

contain  the  distribution  of  the  special  nerve  of  smell. 
Nerve  (Gr.  vevpov,  neuron,  a  cord  or  string).    A  glistening,  white  cord  of 

cylindrical  shape,  connecting  the  brain  or  spinal  cord  with  some  other 

organ  of  the  body. 
Nerve  Cell.     A  minute,  round  and  ashen-gray  cell  found  in  the  brain  and 

other  nervous  centres. 
Nerve  Fi'bre.    An  exceedingly  slender  thread  of  nervous  tissue  found  in 


GLOSSARY  377 

the  various  nervous  organs,  but  especially  in  the  nerves;  it  is  of  a 

white  color. 

Nu-tri'tion  (L.  nu'frio,  to  nourish).    The  processes  by  which  the  nour- 
ishment of  the  body  is  accomplished. 

(E-soph'a-gus  (Gr.).    Literally,'  that  which  carries  food;  the  tube  lead- 
ing from  the  throat  to  the  stomach ;  the  gullet 
0-le-ag'i-nous   (L.  o'leum,   oil).    Of  the  nature  of  oil :  applied  to  an 

important  group  of  food  principles  —  the  fats. 
01-fac'to-ry  (L.  oJfa'cio,  to  smell).     Pertaining  to  the  sense  of  smell. 
Oph-thal'mo-scope  (Gr.  .600a\Aufc,  ophthalmos,  the  eye,  and  o-/co7r<?o>,  skopeo, 

to  look  at).     An  instrument  devised  for  examining  the  interior  of  the 

globe  of  the  eye. 
Op'tic  (Gr.  6pdw,  tyo/wu,  fut.  opsomai,  to  see).    Pertaining  to  the  sense 

of  sight. 
Or'bit  (L.  or'bis,  the  socket).     The  bony  socket  or  cavity  in  which  the 

eyeball  is  situated. 
Os'mose  (Gr.  uvfjAs,  osmos,  a  thrusting  or  impulsion).    The  process  by 

which  liquids  are  impelled  through  a  moist  membrane. 
Os'se-ous  (L.  os,  a  bone).     Consisting  of,  or  resembling  bone. 
Pal'ate  (L.  pala'tum,  the  palate).     The  roof  of  the  mouth,  consisting  of 

the  hard  and  soft  palate. 
Pal'mar.    Relating  to  the  palm  of  the  hand. 
Pan'cre-as  (Gr.  irdv,p"an1  all,  and  Kp&$,  kreas,  flesh).     A  long,  flat  gland 

situated  near  the  stomach ;  in  the  lower  animals  the  analogous  organ 

is  called  the  sweet-bread. 
Pa-pil'lae  (L.  papil'la}.     The  minute  prominences  in  which  terminate 

the  ultimate  fibres  of  the  nerves  of  touch  and  taste. 
Pa-ral'y-sis.    A  disease  of  the  nervous  system  marked  by  the  loss  of 

sensation,  or  voluntary  motion,  or  both  ;  palsy. 
Par-a-ple'gi-a  (Gr.  Tra/mTrXifavw,  paraplesso,  to  strike  amiss).    A  form  of 

paralysis  affecting  the  lower  half  of  the  body. 

Pa-tel'la  (L.  dim.  of  pat'ina,  a  pan).     The  knee-pan  ;  a  small  bone. 
Pel 'vis  (L.).    Literally,  a  basin;  the  bony  cavity  at  the  lower  part  of 

the  trunk. 
Pep'sin  (Gr.  TT&TTW,  pepto,  to  digest).     The  organic  principle  of  the 

gastric  juice. 
Per-i-car'di-um  (Gr.  irepi,  peri,  and  Kapdia,  kardia,  the  heart).     A  porous 

membrane  enclosing  the  heart,  and  secreting  a  lubricating  fluid. 
Per-i-stal'tic  Move'ments  (Gr.  Trepto-rAXu;,  peristello,  to  contract).    The 

slow,  wave-like  movements  of  the  stomach  and  intestines. 
Per-i-to-ne'um  (Gr.  Trepireivu,  periteino,  to  stretch  around)..  The  invest- 
ing membrane  of  the  stomach,  intestines,  and  other  abdominal  organs. 
Per-spi-ra'tion  (L.  perspi'ro,  to  breathe  through).     The  sweat,  or  watery 

exhalation  of  the  skin  ;  when  visible,  it  is  called  sensible  perspiration  ; 

when  invisible,  it  is  called  insensible  perspiration. 


378  GLOSSARY 

Pe'trous  (Gr.  TrtTpa, petra,  a  rock).  The  name  of  the  hard  portion  of  the 
temporal  bone,  in  which  is  situated  the  drum  of  the  ear  and  labyrinth. 

Phar'ynx  (Gr.  <j>dpvy£,  pharunx,  the  -throat).  The  cavity  between  the 
back  of  the  mouth  and  gullet. 

Phys-i-ol'o-gy  (Gr.  0ucrts,  phusis,  nature,  and  \67os,  logos,  a  discourse). 
The  science  of  the  functions  of  living,-  organized  beings. 

Pi'a  Ma'ter  (L.).  Literally,  the  tender  mother;  the  innermost  of  the 
three  coverings  of  the  brain.  It  is  thin  and  delicate  ;  hence  the  name. 

Pleu'ra  (Gr.  ir\evpd,  a  rib).  A  membrane  covering  the  lung  and  lining 
the  chest.  There  is  one  for  each  lung. 

Pleu'ri-sy.    An  inflammation  affecting  the  pleura. 

Pneu-mo-gas'tric  (Gr.  irvev^wv,  pneumon,  the  lungs,  and  yavTrip,  gaster, 
the  stomach).  The  name  of  a  nerve  distributed  to  the  lungs  and 
stomach  ;  it  is  the  principal  nerve  of  respiration. 

Pneu-mo'ni-a  (Gr.).  An  inflammation  affecting  the  air-cells  of  the 
lungs. 

Pres-by-o'pi-a  (Gr.  irptapvs, presbus,  old,  and  £$,  ops,  the  eye).  A  defect 
of  the  accommodation  of  the  eye,  caused  by  the  hardening  of  the 
crystalline  lens  ;  the  "far-sight"  of  adults  and  aged  persons. 

Proc'ess  (L.  proce'do,  proces'sus,  to  proceed,  to  go  forth).  Any  projec- 
tion from  a  surface.  Also,  a  method  of  performance  ;  a  procedure. 

Pty'a-lin  (Gr.  TTTVO\OV,  ptualon,  saliva).  The  peculiar  organic  ingre- 
dient of  the  saliva. 

Pul'mo-na-ry  (L.  pul'mo,  pulmo'nis,  the  lungs).     Pertaining  to  the  lungs. 

Pulse  (L.  pel'lo,  pul'sum,  to  beat).  The  striking  of  an  artery  against 
the  finger,  occasioned  by  the  contraction  of  the  heart,  commonly  felt 
at  the  wrist. 

Pu'pil  (L.  pupil'la).  The  central,  round  opening  in  the  iris,  through 
which  light  passes  into  the  depths  of  the  eye. 

Py-lo'rus  (L.  7ru\itp6s,  puloros,  a  gate-keeper).  The  lower  opening  of 
the  stomach,  at  the  beginning  of  the  small  intestine. 

Re 'flex  Action.  An  involuntary  action  of  the  nervous  system,  by  which 
an  external  impression  conducted  by  a  sensory  nerve  is  reflected,  or 
converted  into  a  motor  impulse. 

Res-pi-ra'tion  (L.  res'piro,  to  breathe  frequently).  The  function  of 
breathing,  comprising  two  acts :  inspiration,  or  breathing  in,  and 
expiration,  or  breathing  out. 

Ret'i-na  (L.  re'te,  a  net).  The  innermost  of  the  three  tunics  or  coats  of 
the  eyeball,  being  an  expansion  of  the  optic  nerve. 

Sac'cha-rine  (L.  sac'charum,  sugar).  Of  the  nature  of  sugar;  applied 
to  the  important  group  of  food  substances  which  embraces  the  dif- 
ferent varieties  of  sugar,  starch,  and  gum. 

Sa-li'va  (L.).  The  moisture  or  fluids  of  the  mouth,  secreted  by  the 
salivary  glands,  etc. 


GLOSSARY  379 

Scle-rot'ic  (Gr.  cr/cXr/pos,  skleros,  hard).     The  tough,  fibrous  outer  tunic 

of  the  eyeball. 
Se-ba'ceous  (L.  se'bum,  fat).     Resembling  fat ;  the  name  of  the  oily 

secretion  by  which  the  skin  is  kept  flexible  and  soft. 
Se-cre'tion  (L.  secer'no,  secre'tum,  to  separate).     The  process  of  separat- 
ing from  the  blood  some  essential  important  fluid;   which  fluid  is 

also  called  a  secretion. 

Sem-i-cir'cu-lar  Canals.    A  portion  of  the  internal  ear. 
Sen-sa'tion.     The  perception  of  an  external  impression  by  the  nervous 

system  ;  a  function  of  the  brain. 
Sen-si-bil'i-ty,  General.    The  power  possessed  by  nearly  all  parts  of  the 

human  body  of  recognizing  the  presence  of  foreign  objects  that  come 

in  contact  with  them. 
Se'rum  (L.).    The  watery  constituent  oj:  the  blood,  which  separates  from 

the  clot  during  the  process  .of  coagulation. 
Skel'e-ton  (Gr.).     The  bony  framework  of  an  animal,  the  different  parts 

of  which  are  maintained  in  their  proper  relative  positions. 
Spec'tro-scope  (from  spec'trum  and  (TKOTT^U,  skopeo,  to  examine  the  spec- 
trum) .    An  instrument  employed  in  the  examination  of  the  spectrum 

of  the  sun  or  any  other  luminous  body. 
Sphyg'mo-graph  (Gr.  o-0iry/i<Ss,  sphugmos,  the  pulse,  and  ypd<f>w,  grapho, 

to  write).     An  ingenious  instrument  by  means  of  which  the  pulse  is 

delineated  upon  paper. 

Sta'pes  (L.)-     Literally,  a  stirrup  ;  one  of  the  small  bones  of  the  tympa- 
num, or  middle  ear,  resembling  somewhat  a  stirrup  in  shape. 
Sym-pa-thet'ic  System  of  Nerves.     A  double  chain  of  nervous  ganglia, 

connected  together  by  numerous  small  nerves,  situated  chiefly  in  front 

of  and  on  each  side  of  the  spinal  column. 
Syn-o'vi-a  (Gr.  <rvv,  sun,  and  wbv,  oon,  egg,  resembling  an  egg).    The 

lubricating  fluid  of  joints,  so  called  because  it  resembles  the  white  of 

egg- 
Sys'to-le  (Gr.  (™<n-<?XXw,  sustello,  to  contract).    The  contraction  of  the 

heart,  by  which  the  blood  is  expelled  from  that  organ. 
Tac-tile  (L.  tac'tus,  touch).     Relating  to  the  sense  of  touch. 
Tem'po-ral  (L.  tem'pus,  time,  and  tem'pora,  the  temples).    Pertaining  to 

the  temples ;   the  name   of  an  artery ;    so  called  because  the  hair 

begins  to  turn  white  with  age  in  that  portion  of  the  scalp. 
Ten'don  (L.  ten' do,  to  stretch).    The  white,  fibrous  cord  or  band  by 

which  a  muscle  is  attached  to  a  bone  ;  a  sinew. 
Tet'a-nus  (Gr.  reivu,  teino,  to  stretch).    A  disease  'marked  by  persistent 

contractions  of  all  or  some  of  the  voluntary  muscles  ;  those  of  the  jaw 

are  sometimes  solely  affected ;  the  disorder  is  then  termed  locked-jaw. 
Tho'rax  (Gr.  66pa£,  thorax,  a  breast-plate).    The  upper  cavity  of  the 

trunk  of  the  body,  containing  the  lungs,  heart,  etc.  j  the  chest. 


380  GLOSSARY 

Thy'roid  (Gr.  8vpe6s,  thureos,  a  shield).  The  largest  of  the  cartilages  of 
the  larynx ;  its  angular  projection  in  the  front  of  the  neck  is  called 
"Adam's  apple." 

Tra'che-a  (Gr.  rpaxtfs,  trachus,  rough).  The  windpipe,  or  the  largest  of 
the  air-passages ;  composed  in  part  of  cartilaginous  rings,  which  render 
its  surface  rough  and  uneven. 

Trans-fu'sion  (L.  transfun'do,  to  pour  from  one  vessel  to  another).  The 
operation  of  injecting  blood  taken  from  one  person  into  the  veins  of 
another ;  other  fluids  than  blood  are  sometimes  used. 

Tri-chi'na  Spi-ra'lis  (L.).  A  minute  species  of  parasite  or  worm,  which 
infests  the  flesh  of  the  hog,  and  which  may  be  introduced  into  the 
human  system  by  eating  pork  not  thoroughly  cooked. 

Tym'pa-num  (Gr.  Tvpiravov,  tumpanon^  a  drum).  The  cavity  of  the 
middle  ear,  resembling  a  drum  in  being  closed  by  two  membranes, 
and  in  having  communication  with  the  atmosphere. 

U're-a  (Gr.).    A  substance  secreted  from  the  blood  by  the  kidneys. 

U'vu-la  (L.  uva,  a  grape).  The  small  pendulous  body  attached  to  the 
back  part  of  the  palate. 

Vas'cu-lar  (L.  vas'culum,  a  little  vessel).  Pertaining  to,  or  containing, 
blood-vessels. 

Ve'nous  (L.  ve'na,  a  vein).    Pertaining  to,  or  contained  within,  a  vein. 

Ven-ti-la'tion.  The  introduction  of  fresh  air  into  "a  room  or  building  in 
such  a  manner  as  to  keep  the  air  within  it  in  a  pure  condition. 

Ven-tril'o-quism  (L.  ven'ter,  the  belly,  and  lo'quor,  to  speak).  A  modifi- 
cation of  natural  speech  by  which  the  voice  is  made  to  appear  to  come 
from  a  distance.  The  ancients  supposed  that  the  voice  was  formed  in 
the  belly  ;  hence  the  name. 

Ven'tri-cles  of  the  heart.  The  two  largest  cavities  of  the  heart,  situated 
at  its  apex  or  point. 

Ver'te-bral  Column  (L.  ver'te-bra,  a  joint).  The  back-bone,  consisting  of 
twenty-six  separate  bones,  called  vertebrae,  firmly  jointed  together ; 
also  called  the  spinal  column  and  spine. 

Ves'ti-bule.  A  portion  of  the  internal  ear,  communicating  with  the  semi- 
circular canals  and  the  cochlea ;  so  called  from  its  fancied  resemblance 
to  the  vestibule  or  porch  of  a  house. 

Vil'li  (L.  vil'lus,  the  nap  of  cloth).  Minute  thread-like  projections  found 
upon  the  internal  surface  of  the  small  intestine,  giving  it  a  velvety 
appearance. 

Vit're-ous  (L.  vi'trum,  glass).  Having  the  appearance  of  glass;  applied 
to  the  humor  occupying  the  largest  part  of  the  cavity  of  the  eyeball. 

Viv-i-sec'tion  (L.  vi'vus,  alive,  and  se'eo,  to  cut).  The  practice  of  oper- 
ating upon  living  animals,  for  the  purpose  of  studying  some 
physiological  process. 

Vocal  Cords.  Two  elastic  bands  or  ridges  situated  in  the  larynx ;  they 
are  the  essential  parts  of  the  organs  of  the  voice. 


INDEX 


A  PAGE 

Abducens  nerves 226 

Absorbent  vessels 137-139 

Absorption  by  the  blood-vessels 137 

by  the  lacteals 138,  141 

of  food 140-141 

Nature  of. 117,186 

Accidents,  First  help  in 342-353 

Accommodation,  Function  of 302-303 

Achilles,  Tendon  of 36 

Adam's  apple 323 

Adipose  tissue 89 

Ague-cake 145 

Air,  Atmospheric 195-196 

Amount  of  in  lungs 200 

Carbonic  acid  in 203-204,  206 

Changes  in,  from  respiration 196-198 

Dust  in  the 202-203 

Effects  of  impure 204-206 

Impurities  in 20l 

Nature's  provision  for  purifying 207 

Air-c*lls  of  the  lungs 139-192 

Air-passages  of  the  lungs 1 SS-192 

Albinos 60 

Albumen 82 

of  the  blood 152 

Albuminoid-  substances 82 

Coagulation  of 82 

Digestion  of. 133 

Properties  of. 82 

Varieties  of 82 

Alcohol,  Abnormal  movements  due  to..     52 

as  a  fat  producer 179-180 

as  a  food....". 109-110 

as  a  medicine  114 

as  a  ration 109 

destructive  to  life 112 

Effects  of,  on  brain 251 

Effects  of,  on  body  temperature...  11 0-1 11 

Effects  of,  on  digestion 145-146 

Effects  of,  on  the  heart 179-180 

Effects  of,  on  the  kidneys 147 

Effects  of,  on  the  liver 146 

Effects  of,  on  the  mind 252 

Effects  of,  on  the  muscles 51 


PAOK 

Alcohol,  Effects  of,  on  respiration 214 

Effects  of,  on  the  special  senses..  ..315-316 

for  thirst 110 

History  of 108 

Hereditary  desire  for 260 

impairs  the  will : 252-253 

Kinds  of. 108-109 

Proi>erties  of. 109 

Proper  and  improper  use  of 112-113 

Poisonous  effects  of. 254 

Spontaneous  combustion  and 213-214 

Strength  and ." 50-51 

Trembling  due  to 251 

AJcoholic  beverages,  Use  of. 114-115 

Alcoholism,  Chronic 255 

Alimentary  canal 119 

Amoeba 14 

Anatomy 18 

Animal  functions 217-218 

Control  of,  by  cerebro-spinal  system . .  219 

Animal  heat,  Production  of 211-213 

Regulation  of. 212-218 

Animals,  Relative  strength  of 40 

Antidotes  for  poison 850-358 

Antitoxine 357 

Apoplexy 244 

Appendicitis 136 

Apple  of  the  eye 294 

Aquaria 209 

Aqueous  humor 292,  299 

Arachnoid  membrane 221 

Arbor  vitae 225 

Arterial  blood 158,  198-199 

differs  from  venous 199-200 

Arteries,  Arrangement  of. 167-168 

Carotid .'....  169 

Hepatic 176 

Histology  of 168 

Pulsation  of 169-170 

Radial 169 

Temporal 169 

Articulations 28 

Arytenoid  cartilage 324 

Asphyxia 849 

Assimilation,  Process  of 117, 17T 


382 


INDEX 


Astigmatism 304 

Auditory  canal 308 

Auditory  nerves 226,  312-313 

Auricles  of  the  heart 161-162,  164 

Axis  cylinder  of  nerve-fibres 219 

B 

Backbone 25 

Bacteria 355 

causing  disease 355-357 

Destructipn  of 358 

Bathing,  among  the  ancients 68 

Importance  of 64 

Time  and  man  ner  of 67 

Baths,  Kinds  of 66 

Belladonna,  Use  of,  as  a  cosmetic 295 

Bicuspid  teeth 121 

Bile,  Accumulation  of,  in  gall-bladder. . .  134 

Secretion  of. 134-135 

Uses  of 135 

Bladder 144 

Bleeding,  how  stopped 178-179,  343 

Blind-spot 296 

Blood,  Arterial 158,  198-199 

Change  of  color  in 158 

Circulation  of 159 

Coagulation  of 155-156 

Color  of 152 

Composition  of 152,  156 

Corpuscles  of 152-155 

Differences  between  venous  and  arte- 
rial  199 

Histology  of 152 

Importance  of 151 

Passage  of,  through  the  heart 163-164 

Eespiratory  changes  in  198 

Supply  of,  in  brain 221 

Venous 171-172 

Blood-vessels,  Absorption  by 137 

Injuries  to 178 

Blushing 231 

Body,  Kenovation  of  th/2 95 

Bone-corpuscle 22 

Bones,  Form  and  composition  of 17-18 

Growth  of 27 

Histology  of 21-22 

of  the  ear 310 

Eepair  of 27-28 

Structure  of .' 19-20 

Usesof 7 

Bow-legs 29 

Brain  219^225 

Effects  of  alcohol  on 251 

Functions  of  the 251 

Injuries  to  the 246-247 

Membranes  of  the 221 

Eeflex  action  of  the 249-250 

Structure  of  the 219,  221 

Bread 102-103 

Breath  of  sick  persons 


PAGE 

Broken  limb,  Management  of 28-29 

Bronchial  tubes 189 

Bronchitis 192 

Burns,  Treatment  of 346 


Caffeine 106 

Canal,  Alimentary 119 

Canals,  Semicircular 312 

Canine  teeth 121 

Capillary  blood-vessels 172-174 

Circulation  in  the 173 

Carbon  dioxide,  exhaled  from  the  lungs.  196 

in  the  air 203-204,  206,  207 

Eetention  of,  in  the  blood 199 

Carotid  artery 169 

Cartilage,  Arytenoid 324 

Cricoid  .  .*. 323 

Inter- vertebral 26 

Kinds  of. 26 

of  the  joints 24 

Thyroid 323 

Caseine 83 

Cataract 299 

Cells 13-14 

Ciliated 191 

Epithelial 140 

Life  of '. .58-60 

Motion  of 16 

Nerve 219,  231-232 

Nourishment  of 15 

Eeproduction  of 15 

Eespiration  of 200 

Structure  of" 14 

Cerebellum,  Function  of 245 

Structure  of 224-225 

Cerebro-spinal  fluid 221 

Cerebro-spinal  nervous  system 219 

Cerebrum,  Function  of 245-248 

Structure  of 222-223 

Cheese 83 

Chest,  Contents  of 23 

Framework  of 22 

Chloral  hydrate,  Effects  of. 258 

Chloroform,  Uses  of 259 

Chocolate 108 

Choke-damp 203 

Chorea 242 

Choroid  coat  of  the  eye 293 

Chyle 135 

Chyme 133 

Cigarette  smoking 257 

Cilia 191-192 

Ciliary  muscle 303 

Circulation 117,  1  :>1  -1  *  1 

in  a  frog's  foot 173 

in  the  veins 171-1 72 

of  the  blood 159 

Eapidity  of 1 75-176 

The  portal  division  of 176 


INDEX 


383 


PAGE 

Circulation,    The    pulmonary    division 
of 176,187 

through  the  heart 163-164 

Climate,  Adaption  to  . .' 212 

Effect  of,  on  appetite 84,  85,  96 

Clothing 69-70 

Rules  regarding 71 

Coagulation  of  blood 155-156 

Coats  of  the  eye 292 

Cocaine 259 

Coccyx 25 

Cochlea 818 

Coffee 87,106 

Effects  of 107 

Collar-bone 23 

Colon 136 

Color-blindness 298 

Alcohol  and 315-316 

Column,  Spinal 25-26 

Columns  of  the  spinal  cord 227 

Complexion 60 

Concha  of  the  ear 807 

Conjunctiva 289 

Consumption  and  foul  air 205-206 

Contraction  of  the  heart 162 

Contraction  of  muscles 37-39 

Convulsions,  Cause  of 242 

Treatment  of .848 

Convolutions  of  the  cerebrum 322-323 

Cooking 99-100 

Cords,  Vocal 324-325 

Cornea 292 

Corpuscles,  Blood 152-155,  198 

Cosmetics 71-72 

Country,  On  going  into  the 365-366 

Cranial  ganglia .' 245 

Cranial  nerves 225-227 

Cranium 221 

Cricoid  cartilage 323 

Crystalline  lens 298-301 

Elasticity  of 303 

Uses  of 299-301 

Cuticle 56-57 

Modified  forms  of 58 

Office  of. 272 

Cutis...  ...57-58 


Decussation  of  motor  and  sensory  fibres 

of  spinal  cord 237-238,  244 

Delirium  tremens 255,  316 

Dentine 12»> 

Dentition  of  infancy 12o 

Dialysis,  Process  of 140 

Diaphragm  ...    22 

Movements  of,  in  respiration 192 

Diastole  of  the  heart 162 

Diet,  The  best '. . . .     88 

Mixed 95-97 

Necessity  of  a  regulated 88 


PACK 

Diet,  Varietyin 89 

Digestion 117-148 

Circumstances  affecting 141-143 

Effects  of  alcohol  on 145-146 

Gastric 182-183 

General  plan  of 119 

how  affected  by  tobacco 147 

Intestinal 134-141 

Nature  of 118 

The  saliva  and 124-128 

Disease,  Bacteria  causing, 855-357 

Germs  of,  in  the  breath 202-203 

Diseases,  of  the  lungs 192 

Respiratory,  among  the  intemperate. .  214 

Disinfectants  and  cleanliness 201 

Disinfection 861-362 

Dislocations 344-345 

Drain  diseases 363 

Drainage 363-365 

at  summer  resorts 366 

Drowning,  Treatment  in  cases  of 349 

Drugs,  Hereditary  desire  for 260 

Drum  of  the  ear 309 

Duct,  Nasal 291 

Thoracic 139 

Dura  mater 221 

Dyspepsia 128 


Ear 306 

Bones  of  the 310 

Cavities  of  the 312 

Drum  of  the 308-309 

External 307-808 

Foreign  bodies  in 315 

Internal 312-313 

Middle 308-312 

Ear  for  music 322 

Ear-sand 812-313 

Ear-stones 312 

Ear-wax 304 

Removal  of 315 

Eggs,  Composition  of 98 

Emotion,  Effects  of,  on  the  heart 165 

Emulsion  of  fats  in  digestion 185 

Endocardium 61 

Endosmosis,  Process  of 139 

Epiglottis,  Uses  of. 190,  324 

Epidermis 56-57 

Eustachian  tube 310-312 

Exercise,  Effects  of 41-42 

Excessive 43,  45 

Importance  of 41 

M<xlesof 43,45-49 

Exosmosis,  Process  of 140 

Expiration 193 

Extensor  muscles 36 

Eye,  Astigmatism  of  the 304 

Defective  formation  of  the 301-304 

Power  of,  of  accommodation 302-303 


384 


INDEX 


PAGE 

Eye,  Structure  of  the 287-301 

Sympathetic  inflammation  of 287 

Eyeball 291-293 

Eyelashes 289 

Eyelids 288-289 


Facial  nerves 226 

Fainting 342-343 

Far-sight 302 

Fats,-  Emulsion  of 83 

in  food 84 

Fenestra  ovalis 813 

Fibres,  Muscular 33-34 

Nervous 219 

Fibrin  in  food 83 

of  the  blood 152, 155-156 

Fire-damp 203 

Fish  as  food 101 

Poisonous 353 

Fits 848 

Flexor  muscles 36 

Follicles 137 

Food,  Absorption  of 140-141 

Animal 97-101 

Daily  quantity  of 93-94 

Experiments  as  to 89 

Inorganic  substances  in 77-81 

Necessity  for 91 

Organic  substances  in 81-87 

Source  of 75 

Vegetable 101-104 

Foods,  Comparative  digestibility  of.  .131-132 

Fractures .28-29,  344-345 

Frost-bites 348 

Fruits  as  food 104 

Functions,  Animal  and  vegetative.  ..217-218 

G 

Ganglia 219 

cranial,  Function  of 245 

of  the  sympathetic  system 230 

Gall-bladder 134 

Gas,  Illuminating 347 

Suffocation  by 347 

Gases,  Interchange  of,  in  the  lungs 199 

Poisonous,  in  the  air 201 

Gastric  digestion 132 

Gastric  juice,  Action  of. 129-180 

Daily  quantity  of 130 

Germs,  Disease,  in  the  breath 202-203 

See  also  Bacteria. 

Glands,  Function  of 118 

Lachrymal 290 

of  the  ear 308 

Perspiratory 61-62 

Salivary 124-125 

Sebaceous 60-61 

Types  of 118 

Glosso-pharyngeal  nerves 226,  277 


PAGH 

Gluten 83 

Glycogen 140,176 

Grog 109 

Gullet 128,  190 

Gum  as  food 87 

Gustatory  nerves. 277 

Gymnastics  and  health 46 

Home 47-4& 

in  schools  and  colleges -. 45-47 

H 

Hair 58-59 

Usesof 59 

Hand,  Mechanism  of  the 36 

Harvey,  William 159 

Hasheesh 259 

Haversian  canals 21 

Health,  Gymnastics  and 46 

Light  and 69-70 

Hearing,  Effects  of.alcohol  on 316 

Injury  to 314-315 

Organ  of. ./.  .306-313 

Protection  of. .'.  .313-314 

Relation  of,  to  speech 322 

Sense  of,  and  sound .'. .  .305-306 

Heart : 160-161 

Action  of  the 162-163 

Activity  of  the 166-167 

Cavities  of  the 161 ,  164 

Circulation  in  the 163-164 

Effects  of  alcohol  on  the 179-180 

Effects  of  tobacco  on  the 181 

Valves  of  the 1 64 

Heart-beats,  Frequency  of  ..164-165,  169-170 

Heart  muscle 35 

Heat,  Animal,  Production  of. 211 

Regulation  of. 212-213 

Hemiplegia 238 

Hemispheres  of  the  cerebrum 222 

Hemorrhage 343 

Hepatic  artery 176 

vein 176 

Heredity,  Desires  resulting  from 260 

House,  Proper  location  of 863 

Humor,  Aqueous 292,  299 

Vitreous 292,  299 

Hunger,  Sensation  of 92-93,  244 

Hydra 218 

Hydrochloric  acid 130 

Hydrophobia 242 

Hygiene <. 13 

Hyperopia 301-302 

Hypoglossal  nerves 227 


Ileo-cfecal  valve 136 

Illuminating  gas 347 

Incisor  teeth 120 

Incus 810 

Inorganic  substances  in  food 77 


385 


PAGE 

Insalivation 124-128 

liiM-ots,  Antidote  for  poison  of 853 

liiM-nsible  perspiration 62 

Inspiration 19? 

I  nu-stinal  juice,  Action  of 135 

Intestines 134-141 

Digestion  in  small 134-136 

Mucous  membrane  of. 135-136 

The  large 136 

Villiof  the 187 

Iris 293-295 

Iron,  Properties  of,  in  the  blood 81 

Properties  of,  in  food 81 


Joints 23-24 

Classification  of » 24 

Juice,  Gastric 129-130 

Intestinal 135 

Pancreatic ,  ..  134 


Kerosene,  Accidents  from 847 

Kidneys 144 

Effects  of  alcohol  on  the 147 

Knock-knees .     29 


Labyrinth 812-313 

Lachrymal  fluid 290 

gland ."290-291 

point 291 

Lacteals,  Absorption  by 138-139 

Lactometer 80 

Laryngoscope 326 

Larynx,  Production  of  the  voice  in 326 

Eapid  growth  of 327 

Structure  of 189-190,  323-326 

Lens,  Crystalline 298-301 

The  convex 334 

Ligaments  23 

Suspensory,  of  the  eye 294 

Light,  Effects  of,  on  health 69 

in  the  sick  room 70 

Theory  of 286 

Lime,  Importance  of 81 

in  the  bones 80 

in  the  food 80-81 

Liver,  Circulation  in 176 

Effects  of  tobacco  on 146-147 

Secretion  of 134 

Locked  jaw 242 

Long-sight 301-^302 

Lungs,  Capacity  of 194 

Diseases  of 192 

Interchange  of  gas  in 199 

Structure  of 187-192 

Lymph 139,  177-178 

Lymphatic  duct 178 

Lymphatic  vessels 139,  177-178 


Magendie  on  pain 268 

Magnesia,  Compounds  of,  in  food 81 

Malleus 310 

Marrow 19 

Spinal 227 

Mastication 119-128 

Importance  of 127 

Meats,  Cooking  and  preservation  of 98-99 

Medulla  oblongata,  Functions  of  the. 243-244 

Structure  of  the 221,  225 

Membrana  tympani 309 

Membrane,  Arachnoid 221 

Dura  mater 221 

Mucous 135-136,  190-191 

Pia  mater 221 

Microscope,  Accessories  to 336,  337 

Choice  and  use  of 

Compound 

Necessity  of 333 

Preliminary  studies  with 337-340 

Simple 334-335 

Milk,  as  a  food 97 

Composition  of 97 

Specific  gravity  of 98 

Milk-teeth 120 

Moderation  £ocietjes 113-114 

Molar  teeth 121 

Morphine 257 

Motor  nerves 234-236 

Mould 356 

Mucous  membrane  of  the  air  passages.  190-191 

of  the  intestines 135-136 

Muscles 33 

Contraction  of 37-39 

Effect  of  alcohol  on 51-52 

Flexion  and  extension  of 35-36 

skeletal,  Structure  of 33-34 

visceral,  Structure  of 35 

Muscular  contraction 37-39 

fibres 33-34 

sense 276 

Myopia 301-302 


Nails,  Care  of  the 65 

Structure  of  the 58-59 

Use.=  of  the 59 

Narco*  ics,  and  digestion 258 

Craving  for 260 

Kinds  of 257 

Sleep  produced  by 260 

Use  of ." 260 

Nasal  cavities 280-281 

duct 291 

Nerve,  Great  sympathetic 231 

Nerve-cells 219 

Nerve-fibres 219 

Properties  of 

Sensory  and  motor 


386 


INDEX 


PAGE 

Nerve-Impulses 219 

Nervous  centres 219 

Nervous  system 217-260 

Cerebro-spinal  .' 219 

Structure  of  the 218-219 

Nervous  tissue,  Properties  of 231-233 

Nerves,  Abducens 226 

Auditory 226,  312-313 

Cranial 225-227 

Facial 226 

Functions  of 233-236 

(Jlosso-pharyngeal 226,  277 

Gustatory 277 

Hypoglossal 227 

Oculomotorius 225 

Olfactory 225,  281-282 

Optic  . . . . ; 825,  286 

Patheticus 226 

Pneumogastric 227,  244 

Spinal 228-229 

Spinal  accessory 227 

Nicotine 256 

Night-air 210 

Nose 281 

Nutrition,  Processes  of 117-118 


Oculoraotorius  nerves 225 

(Esophagus 128 

Oils,  Emulsion  of 83 

in  food 84 

Old-sight 304 

Olfactory  nerves 225,  281-282 

Opiates,  Effects  of 258 

Opium,  Physiological  effects  of 257-258 

Optic  nerves 225,  286 

Specific  energy  of 296 

Orbicular  bone 310 

Orbit  of  the  eye 288 

Organic  substances  as  food 81 

Organs  of  circulation 1 60 

of  digestion 119 

of  hearing 306 

of  .respiration 187-188 

of  sight .287-288 

of  speech 323 

of  the  animal  functions 218 

Osmosis,  Process  of 139 

Ossicles 309 

Oxidation 208 

Oxygen,  Amount  of,  absorbed  daily 200 

and  animal  heat : 211 

Effect  of,  on  venous  blood .198-200 

in  respiration 186 

in  the  cells. ..  ..  200 


Pain,  Relation  of,  to  pleasure 268 

Sensation  of 267 

Use  of. , 


PAGE 

Palsy  of  drunkards 316 

Pancreatic  juice,  Uses  of  the 134-135,  187 

Pancreatin 135 

Papillae,  of  the  cutis 58 

of  the  tongue 277 

Sensitory  nerves  in 271 

Paralysis 238 

Paraplegia 236 

Patheticus  nerves 226 

Pelvis 22 

Pepsin 130 

Peptone 133 

Pericardium ' 1C1 

Perimysium 33 

Peristaltic  action  of  the  stomach 131 

Peritoneum 134 

Perspiration,  Effects  of  interrupted..  ..62-64 

Sensible  and  insensible 62 

Uses  of 62 

Perspiratory  glands 61-62,  118 

Physical  culture 44 

Physiology,  Human 13 

Pia  mater 221 

Plasma,  Composition  of 152 

in  the  tissue  cells 177-178 

Pleura 188 

Pleurisy 192 

Pneumogastric  nerves 227,  244 

Pneumonia 192 

Poison*  and  their  antidotes 350-353 

Portal  vein 176 

Posture,  Habits  of 29 

Potash  in  food 81 

Potato 103 

Presbyopia 304 

Protoplasm 14-15 

Ptomaines 357 

Ptyalin 126 

Pulsation  of  the  arteries 168,  169 

of  the  heart 166,  169 

Pulse 164,  169-170 

Pulse- writer 170 

Pupil  of  the  eye 294 

Pyloris 129 

R 

Radial  artery 169 

Recreation  47 

Red  corpuscles  of  the  blood 152-153 

Reflex  action  of  brain 249-250 

Reflex  action  of  the  spinal  cord 288 

Excess  of 242 

Requisites  for 240 

Uses  of 240-243 

Rennet 83 

Respiration,  Amount  of  labor  in 200-201 

Control  of 194 

Effect  of  alcohol  upon 214 

Effect  of,  on  the  blood 198 

Frequency  of 193 


IXDEX 


387 


PAGE 

Respiration,  Movements  of 192-193 

Object  of 1^7 

Organs  of l>7-l(.»-_' 

Rest,  Necessity  for 49-50 

lit-tina 295-298 

JMinal  linages,  Character  of 299-301 

Kmlurance  of 296-297 

Uibs,  Movements  of,  in  respiration 192 


Saccharine  substances 85 

Sacrum 25 

St.  Vitus's  Dance 242 

Sarcolemma 34 

Saliva,  Action  of,  in  digestion 124-128 

Action  of,  on  the  teeth 123 

Secretion  of. 124, 

Salivary  glands 124-125 

Salt,  Common 78-80 

Importance  of,  as  food 79-80 

Scalds,  Treatment  of 346 

Scars  from  burns 346-347 

Sclerotic  coat  of  the  eyeball 293 

Sea-bathing 66-67 

Sebaceous  glands 60-61,  118 

Semicircular  canals 312,  313 

Sensations,  of  pain 267-268 

of  temperature 275 

of  weight 275 

Production  of 264-265 

Special 269-27 1 

Variety  of. 265 

Sense  of  hearing 305-315 

of  sight 285-304 

of  smell 280-284 

of  taste 27C.--XI 

of  touch 58,  271-275 

Muscular 276 

Thermal 275 

Sensibility,  General,  of  the  body 266 

Sensory  nerves 234-236 

Serpent,  Antidote  for  poison  of 353 

Sewers,  Dangers  from 364 

Shock,  Treatment  for 342 

Short-sight 301-302 

Sick-room,  Care  of 359-361 

Sight,  Effect  of  alcohol  on 316 

Effect  of  tobacco  on 316 

Function  of 285 

Loss  of 287 

Nerve  of 286 

Organ  of 287-301 

Sinews 36-37 

Skeleton 22-23 

Changes  in  the 28-29 

Skin,  Care  of  the 65 

Structure  of  the 56 

Skull,  The,  and  its  uses 22-23 

Sleep,  Amount  required 50 

Necessity  for *-....    49 


PAGE 

Smell,  Nerve  of .281-282 

Organ  of. 280-281 

Relation  of,  to  taste 279-280 

Uses  of 282-284 

Smoking,  Effects  of 255-256 

Cigarette 25T 

Snuff-taking 25T 

Soda  in  food 81 

Sound,  Theory  of 305-306 

Special  senses,  Mutual  relations  of 270 

Spectroscope 158 

Speech,  Relation  of,  to  hearing 822 

The  voice  and 321-322 

Sphygmograph,  The 170 

Spleen 145 

Spinal  accessory  nerves 227 

Spinal  column 25 

Curvature  of  the 26-27 

Spinal  cord,  Direction  of  fibres  in  .. .237-238 

Functions  of 286-287 

Membranes  of 221 

Reflex  action  of 238-243 

Structure  of 227-228 

Spinal  nerves 228-229 

Origin  of  the 22T 

Spontaneous  combustion 218 

Alcohol  the  cause  of 213-214 

Sprains 28 

Treatment  of 346 

Stapes 310 

Starch,  Change  of,  into  sugar 8T 

in  food 86 

Properties  of 86 

Stimulating  substances 87 

Stimulation,  Effects  of  mild 253 

Stomach •. 128-129 

Digestion  in 132-133 

Movements  of 131 

Secretions  of 129-130 

Strength,  Alcohol  and 50-51 

Physical -  40 

Suffocation 199 

by  illuminating  gas 347 

Sugars,  Source  of,  in  food 85 

Varieties  of 85-86 

Sun-bath , 68-69 

Sunstroke 348 

Sympathetic  system 219,  230-231 

Systole  of  the  heart 162 


Tactus  eruditus 275 

Taste,  Education  of 280 

Effect  of  alcohol  on 316 

Organ  of 276-277 

Relation  of,  to  other  senses 279-280 

Sense  of 277-278 

Tea,  Effects  of 87,  107-108 

Tears , 290-291 

Teeth,  Arrangement  of 121 


388 


INDEX 


PAGE 

Teeth,  Bicuspid 121 

Canine 121 

Incisor 120 

Molar 121 

of  different  animals 122 

>  Preservation  of 123 

Renewal  of 120 

Structure  of 120 

Temperature,  Extremes  of 213 

of  animals 211 

of  the  body 212,  213 

of  the  sick  room 360 

Sensation  of 275 

Temporal  artery 169 

Tendon  of  Achilles 36 

Tendons 34,  36-37 

Tetanus 242 

Theine 107 

Theobroma 108 

Thermae 68 

Thirst,  Nature  of 92-93 

Nervous  organ  of 244 

Thoracic  duct 139 

Thorax 139 

Throat-deafness 312 

Thyroid  cartilage 323 

Tickling 266 

Tissues,  Law  of  the 833 

Microscopic  study  of  human 339 

of  inferior  animals 339-340 

Tobacco  as  a  poison 256 

Effect  of,  on  digestion 147 

Effect  of,  on  the  heart 181 

Effect  of,  on  the  young 256 

Tobacco-heart 256 

Tongue 276-278 

in  speech 327 

Touch,  Delicacy  of 274-275 

Organs  of. 271-272 

Relation  of,  to  taste 279 

Sense  of. 58,  272-274 

Toxines 357 

Trachea 188-189 

Transfusion  of  blood 157 

Traps  in  drains 363 

Trichina  spiralis 101 

Trunk 22 

Trypsin : .  135 

Tunics  of  the  eyeball 292 

Tympanum  of  the  ear 308-312 


Urea 144 

ttreter 144 


PAGB 

VTalves,  Ileocaecal 136 

of  heart 164 

of  the  veins 171 

Vapor  of  exhaled  breath 196 

Vegetable  food 96,  101 

Vegetative  functions 217-218 

Sympathetic  system  and 219 

Vein,  Hepatic 176 

Portal 176 

Veins,  Structure  of 170-171 

Vena  cava 176 

Venous  blood 158,  198-199 

Change  of,  in  respiration 200 

Ventilation 209-210 

of  the  cellar 363 

of  the  sick  room 360-361 

Ventricles  of  the  heart 161-162 

of  the  larynx 325 

Ventriloquism 329-330 

Vermiform  appendix 136 

Vertebrae 25 

Vertigo 843 

Vestibule  of  the  ear 312-313 

Villi,  Absorption  by 137-138 

Vital  knot 244 

Vocal  cords 189,  324-525 

Voice  and  speech 321-322 

Organ  of 323-326 

Production  of 326-327 

Eange  of 328 

Varieties  of 327 


W 

Walking  as  a  means  of  exercise 48 

Waste,  Repair  and 91,  92 

Waste-pipes 363 

Wate,r,  Action  of,  on  lead 105-106 

from  springs  and  wells 104-105 

in  exhaled  breath 196 

Proportion  of,  in  the  tissues  and  fluids 

of  thebody 77 

Purity  of 104 

Water-seal 363 

Weight,  Sensation  of 275 

Wells,  Pollution  of 364-365 

White  corpuscles  of  the  blood 154 

Winking 291 


Yeast 856 


or  THE 
UNIVERSITY 


OF 


Y.B  65523 


UNIVERSITY  OF  CALIFORNI 



~S  DUE  ON  THE 


